diff options
Diffstat (limited to 'Documentation')
46 files changed, 2430 insertions, 741 deletions
diff --git a/Documentation/ABI/obsolete/dv1394 b/Documentation/ABI/obsolete/dv1394 deleted file mode 100644 index 2ee36864ca10..000000000000 --- a/Documentation/ABI/obsolete/dv1394 +++ /dev/null @@ -1,9 +0,0 @@ -What: dv1394 (a.k.a. "OHCI-DV I/O support" for FireWire) -Contact: linux1394-devel@lists.sourceforge.net -Description: - New application development should use raw1394 + userspace libraries - instead, notably libiec61883 which is functionally equivalent. - -Users: - ffmpeg/libavformat (used by a variety of media players) - dvgrab v1.x (replaced by dvgrab2 on top of raw1394 and resp. libraries) diff --git a/Documentation/ABI/removed/dv1394 b/Documentation/ABI/removed/dv1394 new file mode 100644 index 000000000000..c2310b6676f4 --- /dev/null +++ b/Documentation/ABI/removed/dv1394 @@ -0,0 +1,14 @@ +What: dv1394 (a.k.a. "OHCI-DV I/O support" for FireWire) +Date: May 2010 (scheduled), finally removed in kernel v2.6.37 +Contact: linux1394-devel@lists.sourceforge.net +Description: + /dev/dv1394/* were character device files, one for each FireWire + controller and for NTSC and PAL respectively, from which DV data + could be received by read() or transmitted by write(). A few + ioctl()s allowed limited control. + This special-purpose interface has been superseded by libraw1394 + + libiec61883 which are functionally equivalent, support HDV, and + transparently work on top of the newer firewire kernel drivers. + +Users: + ffmpeg/libavformat (if configured for DV1394) diff --git a/Documentation/ABI/removed/raw1394 b/Documentation/ABI/removed/raw1394 new file mode 100644 index 000000000000..490aa1efc4ae --- /dev/null +++ b/Documentation/ABI/removed/raw1394 @@ -0,0 +1,15 @@ +What: raw1394 (a.k.a. "Raw IEEE1394 I/O support" for FireWire) +Date: May 2010 (scheduled), finally removed in kernel v2.6.37 +Contact: linux1394-devel@lists.sourceforge.net +Description: + /dev/raw1394 was a character device file that allowed low-level + access to FireWire buses. Its major drawbacks were its inability + to implement sensible device security policies, and its low level + of abstraction that required userspace clients do duplicate much + of the kernel's ieee1394 core functionality. + Replaced by /dev/fw*, i.e. the <linux/firewire-cdev.h> ABI of + firewire-core. + +Users: + libraw1394 (works with firewire-cdev too, transparent to library ABI + users) diff --git a/Documentation/ABI/removed/raw1394_legacy_isochronous b/Documentation/ABI/removed/raw1394_legacy_isochronous deleted file mode 100644 index 1b629622d883..000000000000 --- a/Documentation/ABI/removed/raw1394_legacy_isochronous +++ /dev/null @@ -1,16 +0,0 @@ -What: legacy isochronous ABI of raw1394 (1st generation iso ABI) -Date: June 2007 (scheduled), removed in kernel v2.6.23 -Contact: linux1394-devel@lists.sourceforge.net -Description: - The two request types RAW1394_REQ_ISO_SEND, RAW1394_REQ_ISO_LISTEN have - been deprecated for quite some time. They are very inefficient as they - come with high interrupt load and several layers of callbacks for each - packet. Because of these deficiencies, the video1394 and dv1394 drivers - and the 3rd-generation isochronous ABI in raw1394 (rawiso) were created. - -Users: - libraw1394 users via the long deprecated API raw1394_iso_write, - raw1394_start_iso_write, raw1394_start_iso_rcv, raw1394_stop_iso_rcv - - libdc1394, which optionally uses these old libraw1394 calls - alternatively to the more efficient video1394 ABI diff --git a/Documentation/ABI/removed/video1394 b/Documentation/ABI/removed/video1394 new file mode 100644 index 000000000000..c39c25aee77b --- /dev/null +++ b/Documentation/ABI/removed/video1394 @@ -0,0 +1,16 @@ +What: video1394 (a.k.a. "OHCI-1394 Video support" for FireWire) +Date: May 2010 (scheduled), finally removed in kernel v2.6.37 +Contact: linux1394-devel@lists.sourceforge.net +Description: + /dev/video1394/* were character device files, one for each FireWire + controller, which were used for isochronous I/O. It was added as an + alternative to raw1394's isochronous I/O functionality which had + performance issues in its first generation. Any video1394 user had + to use raw1394 + libraw1394 too because video1394 did not provide + asynchronous I/O for device discovery and configuration. + Replaced by /dev/fw*, i.e. the <linux/firewire-cdev.h> ABI of + firewire-core. + +Users: + libdc1394 (works with firewire-cdev too, transparent to library ABI + users) diff --git a/Documentation/ABI/testing/sysfs-devices-system-ibm-rtl b/Documentation/ABI/testing/sysfs-devices-system-ibm-rtl new file mode 100644 index 000000000000..b82deeaec314 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-system-ibm-rtl @@ -0,0 +1,22 @@ +What: state +Date: Sep 2010 +KernelVersion: 2.6.37 +Contact: Vernon Mauery <vernux@us.ibm.com> +Description: The state file allows a means by which to change in and + out of Premium Real-Time Mode (PRTM), as well as the + ability to query the current state. + 0 => PRTM off + 1 => PRTM enabled +Users: The ibm-prtm userspace daemon uses this interface. + + +What: version +Date: Sep 2010 +KernelVersion: 2.6.37 +Contact: Vernon Mauery <vernux@us.ibm.com> +Description: The version file provides a means by which to query + the RTL table version that lives in the Extended + BIOS Data Area (EBDA). +Users: The ibm-prtm userspace daemon uses this interface. + + diff --git a/Documentation/ABI/testing/sysfs-driver-hid-roccat-pyra b/Documentation/ABI/testing/sysfs-driver-hid-roccat-pyra new file mode 100644 index 000000000000..ad1125b02ff4 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-hid-roccat-pyra @@ -0,0 +1,98 @@ +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/actual_cpi +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: It is possible to switch the cpi setting of the mouse with the + press of a button. + When read, this file returns the raw number of the actual cpi + setting reported by the mouse. This number has to be further + processed to receive the real dpi value. + + VALUE DPI + 1 400 + 2 800 + 4 1600 + + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/actual_profile +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: When read, this file returns the number of the actual profile in + range 0-4. + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/firmware_version +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: When read, this file returns the raw integer version number of the + firmware reported by the mouse. Using the integer value eases + further usage in other programs. To receive the real version + number the decimal point has to be shifted 2 positions to the + left. E.g. a returned value of 138 means 1.38 + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/profile_settings +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: The mouse can store 5 profiles which can be switched by the + press of a button. A profile is split in settings and buttons. + profile_settings holds informations like resolution, sensitivity + and light effects. + When written, this file lets one write the respective profile + settings back to the mouse. The data has to be 13 bytes long. + The mouse will reject invalid data. + Which profile to write is determined by the profile number + contained in the data. + This file is writeonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/profile[1-5]_settings +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: The mouse can store 5 profiles which can be switched by the + press of a button. A profile is split in settings and buttons. + profile_settings holds informations like resolution, sensitivity + and light effects. + When read, these files return the respective profile settings. + The returned data is 13 bytes in size. + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/profile_buttons +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: The mouse can store 5 profiles which can be switched by the + press of a button. A profile is split in settings and buttons. + profile_buttons holds informations about button layout. + When written, this file lets one write the respective profile + buttons back to the mouse. The data has to be 19 bytes long. + The mouse will reject invalid data. + Which profile to write is determined by the profile number + contained in the data. + This file is writeonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/profile[1-5]_buttons +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: The mouse can store 5 profiles which can be switched by the + press of a button. A profile is split in settings and buttons. + profile_buttons holds informations about button layout. + When read, these files return the respective profile buttons. + The returned data is 19 bytes in size. + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/startup_profile +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: The integer value of this attribute ranges from 0-4. + When read, this attribute returns the number of the profile + that's active when the mouse is powered on. + This file is readonly. + +What: /sys/bus/usb/devices/<busnum>-<devnum>:<config num>.<interface num>/settings +Date: August 2010 +Contact: Stefan Achatz <erazor_de@users.sourceforge.net> +Description: When read, this file returns the settings stored in the mouse. + The size of the data is 3 bytes and holds information on the + startup_profile. + When written, this file lets write settings back to the mouse. + The data has to be 3 bytes long. The mouse will reject invalid + data. diff --git a/Documentation/ABI/testing/sysfs-module b/Documentation/ABI/testing/sysfs-module new file mode 100644 index 000000000000..cfcec3bffc0a --- /dev/null +++ b/Documentation/ABI/testing/sysfs-module @@ -0,0 +1,12 @@ +What: /sys/module/pch_phub/drivers/.../pch_mac +Date: August 2010 +KernelVersion: 2.6.35 +Contact: masa-korg@dsn.okisemi.com +Description: Write/read GbE MAC address. + +What: /sys/module/pch_phub/drivers/.../pch_firmware +Date: August 2010 +KernelVersion: 2.6.35 +Contact: masa-korg@dsn.okisemi.com +Description: Write/read Option ROM data. + diff --git a/Documentation/DocBook/80211.tmpl b/Documentation/DocBook/80211.tmpl new file mode 100644 index 000000000000..19a1210c2530 --- /dev/null +++ b/Documentation/DocBook/80211.tmpl @@ -0,0 +1,495 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE set PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> +<set> + <setinfo> + <title>The 802.11 subsystems – for kernel developers</title> + <subtitle> + Explaining wireless 802.11 networking in the Linux kernel + </subtitle> + + <copyright> + <year>2007-2009</year> + <holder>Johannes Berg</holder> + </copyright> + + <authorgroup> + <author> + <firstname>Johannes</firstname> + <surname>Berg</surname> + <affiliation> + <address><email>johannes@sipsolutions.net</email></address> + </affiliation> + </author> + </authorgroup> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License version 2 as published by the Free Software Foundation. + </para> + <para> + This documentation is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + <para> + You should have received a copy of the GNU General Public + License along with this documentation; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + + <abstract> + <para> + These books attempt to give a description of the + various subsystems that play a role in 802.11 wireless + networking in Linux. Since these books are for kernel + developers they attempts to document the structures + and functions used in the kernel as well as giving a + higher-level overview. + </para> + <para> + The reader is expected to be familiar with the 802.11 + standard as published by the IEEE in 802.11-2007 (or + possibly later versions). References to this standard + will be given as "802.11-2007 8.1.5". + </para> + </abstract> + </setinfo> + <book id="cfg80211-developers-guide"> + <bookinfo> + <title>The cfg80211 subsystem</title> + + <abstract> +!Pinclude/net/cfg80211.h Introduction + </abstract> + </bookinfo> + <chapter> + <title>Device registration</title> +!Pinclude/net/cfg80211.h Device registration +!Finclude/net/cfg80211.h ieee80211_band +!Finclude/net/cfg80211.h ieee80211_channel_flags +!Finclude/net/cfg80211.h ieee80211_channel +!Finclude/net/cfg80211.h ieee80211_rate_flags +!Finclude/net/cfg80211.h ieee80211_rate +!Finclude/net/cfg80211.h ieee80211_sta_ht_cap +!Finclude/net/cfg80211.h ieee80211_supported_band +!Finclude/net/cfg80211.h cfg80211_signal_type +!Finclude/net/cfg80211.h wiphy_params_flags +!Finclude/net/cfg80211.h wiphy_flags +!Finclude/net/cfg80211.h wiphy +!Finclude/net/cfg80211.h wireless_dev +!Finclude/net/cfg80211.h wiphy_new +!Finclude/net/cfg80211.h wiphy_register +!Finclude/net/cfg80211.h wiphy_unregister +!Finclude/net/cfg80211.h wiphy_free + +!Finclude/net/cfg80211.h wiphy_name +!Finclude/net/cfg80211.h wiphy_dev +!Finclude/net/cfg80211.h wiphy_priv +!Finclude/net/cfg80211.h priv_to_wiphy +!Finclude/net/cfg80211.h set_wiphy_dev +!Finclude/net/cfg80211.h wdev_priv + </chapter> + <chapter> + <title>Actions and configuration</title> +!Pinclude/net/cfg80211.h Actions and configuration +!Finclude/net/cfg80211.h cfg80211_ops +!Finclude/net/cfg80211.h vif_params +!Finclude/net/cfg80211.h key_params +!Finclude/net/cfg80211.h survey_info_flags +!Finclude/net/cfg80211.h survey_info +!Finclude/net/cfg80211.h beacon_parameters +!Finclude/net/cfg80211.h plink_actions +!Finclude/net/cfg80211.h station_parameters +!Finclude/net/cfg80211.h station_info_flags +!Finclude/net/cfg80211.h rate_info_flags +!Finclude/net/cfg80211.h rate_info +!Finclude/net/cfg80211.h station_info +!Finclude/net/cfg80211.h monitor_flags +!Finclude/net/cfg80211.h mpath_info_flags +!Finclude/net/cfg80211.h mpath_info +!Finclude/net/cfg80211.h bss_parameters +!Finclude/net/cfg80211.h ieee80211_txq_params +!Finclude/net/cfg80211.h cfg80211_crypto_settings +!Finclude/net/cfg80211.h cfg80211_auth_request +!Finclude/net/cfg80211.h cfg80211_assoc_request +!Finclude/net/cfg80211.h cfg80211_deauth_request +!Finclude/net/cfg80211.h cfg80211_disassoc_request +!Finclude/net/cfg80211.h cfg80211_ibss_params +!Finclude/net/cfg80211.h cfg80211_connect_params +!Finclude/net/cfg80211.h cfg80211_pmksa +!Finclude/net/cfg80211.h cfg80211_send_rx_auth +!Finclude/net/cfg80211.h cfg80211_send_auth_timeout +!Finclude/net/cfg80211.h __cfg80211_auth_canceled +!Finclude/net/cfg80211.h cfg80211_send_rx_assoc +!Finclude/net/cfg80211.h cfg80211_send_assoc_timeout +!Finclude/net/cfg80211.h cfg80211_send_deauth +!Finclude/net/cfg80211.h __cfg80211_send_deauth +!Finclude/net/cfg80211.h cfg80211_send_disassoc +!Finclude/net/cfg80211.h __cfg80211_send_disassoc +!Finclude/net/cfg80211.h cfg80211_ibss_joined +!Finclude/net/cfg80211.h cfg80211_connect_result +!Finclude/net/cfg80211.h cfg80211_roamed +!Finclude/net/cfg80211.h cfg80211_disconnected +!Finclude/net/cfg80211.h cfg80211_ready_on_channel +!Finclude/net/cfg80211.h cfg80211_remain_on_channel_expired +!Finclude/net/cfg80211.h cfg80211_new_sta +!Finclude/net/cfg80211.h cfg80211_rx_mgmt +!Finclude/net/cfg80211.h cfg80211_mgmt_tx_status +!Finclude/net/cfg80211.h cfg80211_cqm_rssi_notify +!Finclude/net/cfg80211.h cfg80211_michael_mic_failure + </chapter> + <chapter> + <title>Scanning and BSS list handling</title> +!Pinclude/net/cfg80211.h Scanning and BSS list handling +!Finclude/net/cfg80211.h cfg80211_ssid +!Finclude/net/cfg80211.h cfg80211_scan_request +!Finclude/net/cfg80211.h cfg80211_scan_done +!Finclude/net/cfg80211.h cfg80211_bss +!Finclude/net/cfg80211.h cfg80211_inform_bss_frame +!Finclude/net/cfg80211.h cfg80211_inform_bss +!Finclude/net/cfg80211.h cfg80211_unlink_bss +!Finclude/net/cfg80211.h cfg80211_find_ie +!Finclude/net/cfg80211.h ieee80211_bss_get_ie + </chapter> + <chapter> + <title>Utility functions</title> +!Pinclude/net/cfg80211.h Utility functions +!Finclude/net/cfg80211.h ieee80211_channel_to_frequency +!Finclude/net/cfg80211.h ieee80211_frequency_to_channel +!Finclude/net/cfg80211.h ieee80211_get_channel +!Finclude/net/cfg80211.h ieee80211_get_response_rate +!Finclude/net/cfg80211.h ieee80211_hdrlen +!Finclude/net/cfg80211.h ieee80211_get_hdrlen_from_skb +!Finclude/net/cfg80211.h ieee80211_radiotap_iterator + </chapter> + <chapter> + <title>Data path helpers</title> +!Pinclude/net/cfg80211.h Data path helpers +!Finclude/net/cfg80211.h ieee80211_data_to_8023 +!Finclude/net/cfg80211.h ieee80211_data_from_8023 +!Finclude/net/cfg80211.h ieee80211_amsdu_to_8023s +!Finclude/net/cfg80211.h cfg80211_classify8021d + </chapter> + <chapter> + <title>Regulatory enforcement infrastructure</title> +!Pinclude/net/cfg80211.h Regulatory enforcement infrastructure +!Finclude/net/cfg80211.h regulatory_hint +!Finclude/net/cfg80211.h wiphy_apply_custom_regulatory +!Finclude/net/cfg80211.h freq_reg_info + </chapter> + <chapter> + <title>RFkill integration</title> +!Pinclude/net/cfg80211.h RFkill integration +!Finclude/net/cfg80211.h wiphy_rfkill_set_hw_state +!Finclude/net/cfg80211.h wiphy_rfkill_start_polling +!Finclude/net/cfg80211.h wiphy_rfkill_stop_polling + </chapter> + <chapter> + <title>Test mode</title> +!Pinclude/net/cfg80211.h Test mode +!Finclude/net/cfg80211.h cfg80211_testmode_alloc_reply_skb +!Finclude/net/cfg80211.h cfg80211_testmode_reply +!Finclude/net/cfg80211.h cfg80211_testmode_alloc_event_skb +!Finclude/net/cfg80211.h cfg80211_testmode_event + </chapter> + </book> + <book id="mac80211-developers-guide"> + <bookinfo> + <title>The mac80211 subsystem</title> + <abstract> +!Pinclude/net/mac80211.h Introduction +!Pinclude/net/mac80211.h Warning + </abstract> + </bookinfo> + + <toc></toc> + + <!-- + Generally, this document shall be ordered by increasing complexity. + It is important to note that readers should be able to read only + the first few sections to get a working driver and only advanced + usage should require reading the full document. + --> + + <part> + <title>The basic mac80211 driver interface</title> + <partintro> + <para> + You should read and understand the information contained + within this part of the book while implementing a driver. + In some chapters, advanced usage is noted, that may be + skipped at first. + </para> + <para> + This part of the book only covers station and monitor mode + functionality, additional information required to implement + the other modes is covered in the second part of the book. + </para> + </partintro> + + <chapter id="basics"> + <title>Basic hardware handling</title> + <para>TBD</para> + <para> + This chapter shall contain information on getting a hw + struct allocated and registered with mac80211. + </para> + <para> + Since it is required to allocate rates/modes before registering + a hw struct, this chapter shall also contain information on setting + up the rate/mode structs. + </para> + <para> + Additionally, some discussion about the callbacks and + the general programming model should be in here, including + the definition of ieee80211_ops which will be referred to + a lot. + </para> + <para> + Finally, a discussion of hardware capabilities should be done + with references to other parts of the book. + </para> + <!-- intentionally multiple !F lines to get proper order --> +!Finclude/net/mac80211.h ieee80211_hw +!Finclude/net/mac80211.h ieee80211_hw_flags +!Finclude/net/mac80211.h SET_IEEE80211_DEV +!Finclude/net/mac80211.h SET_IEEE80211_PERM_ADDR +!Finclude/net/mac80211.h ieee80211_ops +!Finclude/net/mac80211.h ieee80211_alloc_hw +!Finclude/net/mac80211.h ieee80211_register_hw +!Finclude/net/mac80211.h ieee80211_get_tx_led_name +!Finclude/net/mac80211.h ieee80211_get_rx_led_name +!Finclude/net/mac80211.h ieee80211_get_assoc_led_name +!Finclude/net/mac80211.h ieee80211_get_radio_led_name +!Finclude/net/mac80211.h ieee80211_unregister_hw +!Finclude/net/mac80211.h ieee80211_free_hw + </chapter> + + <chapter id="phy-handling"> + <title>PHY configuration</title> + <para>TBD</para> + <para> + This chapter should describe PHY handling including + start/stop callbacks and the various structures used. + </para> +!Finclude/net/mac80211.h ieee80211_conf +!Finclude/net/mac80211.h ieee80211_conf_flags + </chapter> + + <chapter id="iface-handling"> + <title>Virtual interfaces</title> + <para>TBD</para> + <para> + This chapter should describe virtual interface basics + that are relevant to the driver (VLANs, MGMT etc are not.) + It should explain the use of the add_iface/remove_iface + callbacks as well as the interface configuration callbacks. + </para> + <para>Things related to AP mode should be discussed there.</para> + <para> + Things related to supporting multiple interfaces should be + in the appropriate chapter, a BIG FAT note should be here about + this though and the recommendation to allow only a single + interface in STA mode at first! + </para> +!Finclude/net/mac80211.h ieee80211_vif + </chapter> + + <chapter id="rx-tx"> + <title>Receive and transmit processing</title> + <sect1> + <title>what should be here</title> + <para>TBD</para> + <para> + This should describe the receive and transmit + paths in mac80211/the drivers as well as + transmit status handling. + </para> + </sect1> + <sect1> + <title>Frame format</title> +!Pinclude/net/mac80211.h Frame format + </sect1> + <sect1> + <title>Packet alignment</title> +!Pnet/mac80211/rx.c Packet alignment + </sect1> + <sect1> + <title>Calling into mac80211 from interrupts</title> +!Pinclude/net/mac80211.h Calling mac80211 from interrupts + </sect1> + <sect1> + <title>functions/definitions</title> +!Finclude/net/mac80211.h ieee80211_rx_status +!Finclude/net/mac80211.h mac80211_rx_flags +!Finclude/net/mac80211.h ieee80211_tx_info +!Finclude/net/mac80211.h ieee80211_rx +!Finclude/net/mac80211.h ieee80211_rx_irqsafe +!Finclude/net/mac80211.h ieee80211_tx_status +!Finclude/net/mac80211.h ieee80211_tx_status_irqsafe +!Finclude/net/mac80211.h ieee80211_rts_get +!Finclude/net/mac80211.h ieee80211_rts_duration +!Finclude/net/mac80211.h ieee80211_ctstoself_get +!Finclude/net/mac80211.h ieee80211_ctstoself_duration +!Finclude/net/mac80211.h ieee80211_generic_frame_duration +!Finclude/net/mac80211.h ieee80211_wake_queue +!Finclude/net/mac80211.h ieee80211_stop_queue +!Finclude/net/mac80211.h ieee80211_wake_queues +!Finclude/net/mac80211.h ieee80211_stop_queues + </sect1> + </chapter> + + <chapter id="filters"> + <title>Frame filtering</title> +!Pinclude/net/mac80211.h Frame filtering +!Finclude/net/mac80211.h ieee80211_filter_flags + </chapter> + </part> + + <part id="advanced"> + <title>Advanced driver interface</title> + <partintro> + <para> + Information contained within this part of the book is + of interest only for advanced interaction of mac80211 + with drivers to exploit more hardware capabilities and + improve performance. + </para> + </partintro> + + <chapter id="hardware-crypto-offload"> + <title>Hardware crypto acceleration</title> +!Pinclude/net/mac80211.h Hardware crypto acceleration + <!-- intentionally multiple !F lines to get proper order --> +!Finclude/net/mac80211.h set_key_cmd +!Finclude/net/mac80211.h ieee80211_key_conf +!Finclude/net/mac80211.h ieee80211_key_flags + </chapter> + + <chapter id="powersave"> + <title>Powersave support</title> +!Pinclude/net/mac80211.h Powersave support + </chapter> + + <chapter id="beacon-filter"> + <title>Beacon filter support</title> +!Pinclude/net/mac80211.h Beacon filter support +!Finclude/net/mac80211.h ieee80211_beacon_loss + </chapter> + + <chapter id="qos"> + <title>Multiple queues and QoS support</title> + <para>TBD</para> +!Finclude/net/mac80211.h ieee80211_tx_queue_params + </chapter> + + <chapter id="AP"> + <title>Access point mode support</title> + <para>TBD</para> + <para>Some parts of the if_conf should be discussed here instead</para> + <para> + Insert notes about VLAN interfaces with hw crypto here or + in the hw crypto chapter. + </para> +!Finclude/net/mac80211.h ieee80211_get_buffered_bc +!Finclude/net/mac80211.h ieee80211_beacon_get + </chapter> + + <chapter id="multi-iface"> + <title>Supporting multiple virtual interfaces</title> + <para>TBD</para> + <para> + Note: WDS with identical MAC address should almost always be OK + </para> + <para> + Insert notes about having multiple virtual interfaces with + different MAC addresses here, note which configurations are + supported by mac80211, add notes about supporting hw crypto + with it. + </para> + </chapter> + + <chapter id="hardware-scan-offload"> + <title>Hardware scan offload</title> + <para>TBD</para> +!Finclude/net/mac80211.h ieee80211_scan_completed + </chapter> + </part> + + <part id="rate-control"> + <title>Rate control interface</title> + <partintro> + <para>TBD</para> + <para> + This part of the book describes the rate control algorithm + interface and how it relates to mac80211 and drivers. + </para> + </partintro> + <chapter id="dummy"> + <title>dummy chapter</title> + <para>TBD</para> + </chapter> + </part> + + <part id="internal"> + <title>Internals</title> + <partintro> + <para>TBD</para> + <para> + This part of the book describes mac80211 internals. + </para> + </partintro> + + <chapter id="key-handling"> + <title>Key handling</title> + <sect1> + <title>Key handling basics</title> +!Pnet/mac80211/key.c Key handling basics + </sect1> + <sect1> + <title>MORE TBD</title> + <para>TBD</para> + </sect1> + </chapter> + + <chapter id="rx-processing"> + <title>Receive processing</title> + <para>TBD</para> + </chapter> + + <chapter id="tx-processing"> + <title>Transmit processing</title> + <para>TBD</para> + </chapter> + + <chapter id="sta-info"> + <title>Station info handling</title> + <sect1> + <title>Programming information</title> +!Fnet/mac80211/sta_info.h sta_info +!Fnet/mac80211/sta_info.h ieee80211_sta_info_flags + </sect1> + <sect1> + <title>STA information lifetime rules</title> +!Pnet/mac80211/sta_info.c STA information lifetime rules + </sect1> + </chapter> + + <chapter id="synchronisation"> + <title>Synchronisation</title> + <para>TBD</para> + <para>Locking, lots of RCU</para> + </chapter> + </part> + </book> +</set> diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index 34929f24c284..8b6e00a71034 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -12,7 +12,7 @@ DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \ kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \ - mac80211.xml debugobjects.xml sh.xml regulator.xml \ + 80211.xml debugobjects.xml sh.xml regulator.xml \ alsa-driver-api.xml writing-an-alsa-driver.xml \ tracepoint.xml media.xml drm.xml diff --git a/Documentation/DocBook/drm.tmpl b/Documentation/DocBook/drm.tmpl index 910c923a9b86..2861055afd7a 100644 --- a/Documentation/DocBook/drm.tmpl +++ b/Documentation/DocBook/drm.tmpl @@ -136,6 +136,7 @@ #ifdef CONFIG_COMPAT .compat_ioctl = i915_compat_ioctl, #endif + .llseek = noop_llseek, }, .pci_driver = { .name = DRIVER_NAME, diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index 6899f471fb15..6b4e07f28b69 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -257,7 +257,8 @@ X!Earch/x86/kernel/mca_32.c !Iblock/blk-sysfs.c !Eblock/blk-settings.c !Eblock/blk-exec.c -!Eblock/blk-barrier.c +!Eblock/blk-flush.c +!Eblock/blk-lib.c !Eblock/blk-tag.c !Iblock/blk-tag.c !Eblock/blk-integrity.c diff --git a/Documentation/DocBook/mac80211.tmpl b/Documentation/DocBook/mac80211.tmpl deleted file mode 100644 index affb15a344a1..000000000000 --- a/Documentation/DocBook/mac80211.tmpl +++ /dev/null @@ -1,337 +0,0 @@ -<?xml version="1.0" encoding="UTF-8"?> -<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" - "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> - -<book id="mac80211-developers-guide"> - <bookinfo> - <title>The mac80211 subsystem for kernel developers</title> - - <authorgroup> - <author> - <firstname>Johannes</firstname> - <surname>Berg</surname> - <affiliation> - <address><email>johannes@sipsolutions.net</email></address> - </affiliation> - </author> - </authorgroup> - - <copyright> - <year>2007-2009</year> - <holder>Johannes Berg</holder> - </copyright> - - <legalnotice> - <para> - This documentation is free software; you can redistribute - it and/or modify it under the terms of the GNU General Public - License version 2 as published by the Free Software Foundation. - </para> - - <para> - This documentation is distributed in the hope that it will be - useful, but WITHOUT ANY WARRANTY; without even the implied - warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. - See the GNU General Public License for more details. - </para> - - <para> - You should have received a copy of the GNU General Public - License along with this documentation; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, - MA 02111-1307 USA - </para> - - <para> - For more details see the file COPYING in the source - distribution of Linux. - </para> - </legalnotice> - - <abstract> -!Pinclude/net/mac80211.h Introduction -!Pinclude/net/mac80211.h Warning - </abstract> - </bookinfo> - - <toc></toc> - -<!-- -Generally, this document shall be ordered by increasing complexity. -It is important to note that readers should be able to read only -the first few sections to get a working driver and only advanced -usage should require reading the full document. ---> - - <part> - <title>The basic mac80211 driver interface</title> - <partintro> - <para> - You should read and understand the information contained - within this part of the book while implementing a driver. - In some chapters, advanced usage is noted, that may be - skipped at first. - </para> - <para> - This part of the book only covers station and monitor mode - functionality, additional information required to implement - the other modes is covered in the second part of the book. - </para> - </partintro> - - <chapter id="basics"> - <title>Basic hardware handling</title> - <para>TBD</para> - <para> - This chapter shall contain information on getting a hw - struct allocated and registered with mac80211. - </para> - <para> - Since it is required to allocate rates/modes before registering - a hw struct, this chapter shall also contain information on setting - up the rate/mode structs. - </para> - <para> - Additionally, some discussion about the callbacks and - the general programming model should be in here, including - the definition of ieee80211_ops which will be referred to - a lot. - </para> - <para> - Finally, a discussion of hardware capabilities should be done - with references to other parts of the book. - </para> -<!-- intentionally multiple !F lines to get proper order --> -!Finclude/net/mac80211.h ieee80211_hw -!Finclude/net/mac80211.h ieee80211_hw_flags -!Finclude/net/mac80211.h SET_IEEE80211_DEV -!Finclude/net/mac80211.h SET_IEEE80211_PERM_ADDR -!Finclude/net/mac80211.h ieee80211_ops -!Finclude/net/mac80211.h ieee80211_alloc_hw -!Finclude/net/mac80211.h ieee80211_register_hw -!Finclude/net/mac80211.h ieee80211_get_tx_led_name -!Finclude/net/mac80211.h ieee80211_get_rx_led_name -!Finclude/net/mac80211.h ieee80211_get_assoc_led_name -!Finclude/net/mac80211.h ieee80211_get_radio_led_name -!Finclude/net/mac80211.h ieee80211_unregister_hw -!Finclude/net/mac80211.h ieee80211_free_hw - </chapter> - - <chapter id="phy-handling"> - <title>PHY configuration</title> - <para>TBD</para> - <para> - This chapter should describe PHY handling including - start/stop callbacks and the various structures used. - </para> -!Finclude/net/mac80211.h ieee80211_conf -!Finclude/net/mac80211.h ieee80211_conf_flags - </chapter> - - <chapter id="iface-handling"> - <title>Virtual interfaces</title> - <para>TBD</para> - <para> - This chapter should describe virtual interface basics - that are relevant to the driver (VLANs, MGMT etc are not.) - It should explain the use of the add_iface/remove_iface - callbacks as well as the interface configuration callbacks. - </para> - <para>Things related to AP mode should be discussed there.</para> - <para> - Things related to supporting multiple interfaces should be - in the appropriate chapter, a BIG FAT note should be here about - this though and the recommendation to allow only a single - interface in STA mode at first! - </para> -!Finclude/net/mac80211.h ieee80211_vif - </chapter> - - <chapter id="rx-tx"> - <title>Receive and transmit processing</title> - <sect1> - <title>what should be here</title> - <para>TBD</para> - <para> - This should describe the receive and transmit - paths in mac80211/the drivers as well as - transmit status handling. - </para> - </sect1> - <sect1> - <title>Frame format</title> -!Pinclude/net/mac80211.h Frame format - </sect1> - <sect1> - <title>Packet alignment</title> -!Pnet/mac80211/rx.c Packet alignment - </sect1> - <sect1> - <title>Calling into mac80211 from interrupts</title> -!Pinclude/net/mac80211.h Calling mac80211 from interrupts - </sect1> - <sect1> - <title>functions/definitions</title> -!Finclude/net/mac80211.h ieee80211_rx_status -!Finclude/net/mac80211.h mac80211_rx_flags -!Finclude/net/mac80211.h ieee80211_tx_info -!Finclude/net/mac80211.h ieee80211_rx -!Finclude/net/mac80211.h ieee80211_rx_irqsafe -!Finclude/net/mac80211.h ieee80211_tx_status -!Finclude/net/mac80211.h ieee80211_tx_status_irqsafe -!Finclude/net/mac80211.h ieee80211_rts_get -!Finclude/net/mac80211.h ieee80211_rts_duration -!Finclude/net/mac80211.h ieee80211_ctstoself_get -!Finclude/net/mac80211.h ieee80211_ctstoself_duration -!Finclude/net/mac80211.h ieee80211_generic_frame_duration -!Finclude/net/mac80211.h ieee80211_wake_queue -!Finclude/net/mac80211.h ieee80211_stop_queue -!Finclude/net/mac80211.h ieee80211_wake_queues -!Finclude/net/mac80211.h ieee80211_stop_queues - </sect1> - </chapter> - - <chapter id="filters"> - <title>Frame filtering</title> -!Pinclude/net/mac80211.h Frame filtering -!Finclude/net/mac80211.h ieee80211_filter_flags - </chapter> - </part> - - <part id="advanced"> - <title>Advanced driver interface</title> - <partintro> - <para> - Information contained within this part of the book is - of interest only for advanced interaction of mac80211 - with drivers to exploit more hardware capabilities and - improve performance. - </para> - </partintro> - - <chapter id="hardware-crypto-offload"> - <title>Hardware crypto acceleration</title> -!Pinclude/net/mac80211.h Hardware crypto acceleration -<!-- intentionally multiple !F lines to get proper order --> -!Finclude/net/mac80211.h set_key_cmd -!Finclude/net/mac80211.h ieee80211_key_conf -!Finclude/net/mac80211.h ieee80211_key_alg -!Finclude/net/mac80211.h ieee80211_key_flags - </chapter> - - <chapter id="powersave"> - <title>Powersave support</title> -!Pinclude/net/mac80211.h Powersave support - </chapter> - - <chapter id="beacon-filter"> - <title>Beacon filter support</title> -!Pinclude/net/mac80211.h Beacon filter support -!Finclude/net/mac80211.h ieee80211_beacon_loss - </chapter> - - <chapter id="qos"> - <title>Multiple queues and QoS support</title> - <para>TBD</para> -!Finclude/net/mac80211.h ieee80211_tx_queue_params - </chapter> - - <chapter id="AP"> - <title>Access point mode support</title> - <para>TBD</para> - <para>Some parts of the if_conf should be discussed here instead</para> - <para> - Insert notes about VLAN interfaces with hw crypto here or - in the hw crypto chapter. - </para> -!Finclude/net/mac80211.h ieee80211_get_buffered_bc -!Finclude/net/mac80211.h ieee80211_beacon_get - </chapter> - - <chapter id="multi-iface"> - <title>Supporting multiple virtual interfaces</title> - <para>TBD</para> - <para> - Note: WDS with identical MAC address should almost always be OK - </para> - <para> - Insert notes about having multiple virtual interfaces with - different MAC addresses here, note which configurations are - supported by mac80211, add notes about supporting hw crypto - with it. - </para> - </chapter> - - <chapter id="hardware-scan-offload"> - <title>Hardware scan offload</title> - <para>TBD</para> -!Finclude/net/mac80211.h ieee80211_scan_completed - </chapter> - </part> - - <part id="rate-control"> - <title>Rate control interface</title> - <partintro> - <para>TBD</para> - <para> - This part of the book describes the rate control algorithm - interface and how it relates to mac80211 and drivers. - </para> - </partintro> - <chapter id="dummy"> - <title>dummy chapter</title> - <para>TBD</para> - </chapter> - </part> - - <part id="internal"> - <title>Internals</title> - <partintro> - <para>TBD</para> - <para> - This part of the book describes mac80211 internals. - </para> - </partintro> - - <chapter id="key-handling"> - <title>Key handling</title> - <sect1> - <title>Key handling basics</title> -!Pnet/mac80211/key.c Key handling basics - </sect1> - <sect1> - <title>MORE TBD</title> - <para>TBD</para> - </sect1> - </chapter> - - <chapter id="rx-processing"> - <title>Receive processing</title> - <para>TBD</para> - </chapter> - - <chapter id="tx-processing"> - <title>Transmit processing</title> - <para>TBD</para> - </chapter> - - <chapter id="sta-info"> - <title>Station info handling</title> - <sect1> - <title>Programming information</title> -!Fnet/mac80211/sta_info.h sta_info -!Fnet/mac80211/sta_info.h ieee80211_sta_info_flags - </sect1> - <sect1> - <title>STA information lifetime rules</title> -!Pnet/mac80211/sta_info.c STA information lifetime rules - </sect1> - </chapter> - - <chapter id="synchronisation"> - <title>Synchronisation</title> - <para>TBD</para> - <para>Locking, lots of RCU</para> - </chapter> - </part> -</book> diff --git a/Documentation/arm/SA1100/FreeBird b/Documentation/arm/SA1100/FreeBird index fb23b770aaf4..ab9193663b2b 100644 --- a/Documentation/arm/SA1100/FreeBird +++ b/Documentation/arm/SA1100/FreeBird @@ -1,6 +1,6 @@ -Freebird-1.1 is produced by Legned(C) ,Inc. +Freebird-1.1 is produced by Legend(C), Inc. http://web.archive.org/web/*/http://www.legend.com.cn -and software/linux mainatined by Coventive(C),Inc. +and software/linux maintained by Coventive(C), Inc. (http://www.coventive.com) Based on the Nicolas's strongarm kernel tree. diff --git a/Documentation/block/00-INDEX b/Documentation/block/00-INDEX index a406286f6f3e..d111e3b23db0 100644 --- a/Documentation/block/00-INDEX +++ b/Documentation/block/00-INDEX @@ -1,7 +1,5 @@ 00-INDEX - This file -barrier.txt - - I/O Barriers biodoc.txt - Notes on the Generic Block Layer Rewrite in Linux 2.5 capability.txt @@ -16,3 +14,5 @@ stat.txt - Block layer statistics in /sys/block/<dev>/stat switching-sched.txt - Switching I/O schedulers at runtime +writeback_cache_control.txt + - Control of volatile write back caches diff --git a/Documentation/block/barrier.txt b/Documentation/block/barrier.txt deleted file mode 100644 index 2c2f24f634e4..000000000000 --- a/Documentation/block/barrier.txt +++ /dev/null @@ -1,261 +0,0 @@ -I/O Barriers -============ -Tejun Heo <htejun@gmail.com>, July 22 2005 - -I/O barrier requests are used to guarantee ordering around the barrier -requests. Unless you're crazy enough to use disk drives for -implementing synchronization constructs (wow, sounds interesting...), -the ordering is meaningful only for write requests for things like -journal checkpoints. All requests queued before a barrier request -must be finished (made it to the physical medium) before the barrier -request is started, and all requests queued after the barrier request -must be started only after the barrier request is finished (again, -made it to the physical medium). - -In other words, I/O barrier requests have the following two properties. - -1. Request ordering - -Requests cannot pass the barrier request. Preceding requests are -processed before the barrier and following requests after. - -Depending on what features a drive supports, this can be done in one -of the following three ways. - -i. For devices which have queue depth greater than 1 (TCQ devices) and -support ordered tags, block layer can just issue the barrier as an -ordered request and the lower level driver, controller and drive -itself are responsible for making sure that the ordering constraint is -met. Most modern SCSI controllers/drives should support this. - -NOTE: SCSI ordered tag isn't currently used due to limitation in the - SCSI midlayer, see the following random notes section. - -ii. For devices which have queue depth greater than 1 but don't -support ordered tags, block layer ensures that the requests preceding -a barrier request finishes before issuing the barrier request. Also, -it defers requests following the barrier until the barrier request is -finished. Older SCSI controllers/drives and SATA drives fall in this -category. - -iii. Devices which have queue depth of 1. This is a degenerate case -of ii. Just keeping issue order suffices. Ancient SCSI -controllers/drives and IDE drives are in this category. - -2. Forced flushing to physical medium - -Again, if you're not gonna do synchronization with disk drives (dang, -it sounds even more appealing now!), the reason you use I/O barriers -is mainly to protect filesystem integrity when power failure or some -other events abruptly stop the drive from operating and possibly make -the drive lose data in its cache. So, I/O barriers need to guarantee -that requests actually get written to non-volatile medium in order. - -There are four cases, - -i. No write-back cache. Keeping requests ordered is enough. - -ii. Write-back cache but no flush operation. There's no way to -guarantee physical-medium commit order. This kind of devices can't to -I/O barriers. - -iii. Write-back cache and flush operation but no FUA (forced unit -access). We need two cache flushes - before and after the barrier -request. - -iv. Write-back cache, flush operation and FUA. We still need one -flush to make sure requests preceding a barrier are written to medium, -but post-barrier flush can be avoided by using FUA write on the -barrier itself. - - -How to support barrier requests in drivers ------------------------------------------- - -All barrier handling is done inside block layer proper. All low level -drivers have to are implementing its prepare_flush_fn and using one -the following two functions to indicate what barrier type it supports -and how to prepare flush requests. Note that the term 'ordered' is -used to indicate the whole sequence of performing barrier requests -including draining and flushing. - -typedef void (prepare_flush_fn)(struct request_queue *q, struct request *rq); - -int blk_queue_ordered(struct request_queue *q, unsigned ordered, - prepare_flush_fn *prepare_flush_fn); - -@q : the queue in question -@ordered : the ordered mode the driver/device supports -@prepare_flush_fn : this function should prepare @rq such that it - flushes cache to physical medium when executed - -For example, SCSI disk driver's prepare_flush_fn looks like the -following. - -static void sd_prepare_flush(struct request_queue *q, struct request *rq) -{ - memset(rq->cmd, 0, sizeof(rq->cmd)); - rq->cmd_type = REQ_TYPE_BLOCK_PC; - rq->timeout = SD_TIMEOUT; - rq->cmd[0] = SYNCHRONIZE_CACHE; - rq->cmd_len = 10; -} - -The following seven ordered modes are supported. The following table -shows which mode should be used depending on what features a -device/driver supports. In the leftmost column of table, -QUEUE_ORDERED_ prefix is omitted from the mode names to save space. - -The table is followed by description of each mode. Note that in the -descriptions of QUEUE_ORDERED_DRAIN*, '=>' is used whereas '->' is -used for QUEUE_ORDERED_TAG* descriptions. '=>' indicates that the -preceding step must be complete before proceeding to the next step. -'->' indicates that the next step can start as soon as the previous -step is issued. - - write-back cache ordered tag flush FUA ------------------------------------------------------------------------ -NONE yes/no N/A no N/A -DRAIN no no N/A N/A -DRAIN_FLUSH yes no yes no -DRAIN_FUA yes no yes yes -TAG no yes N/A N/A -TAG_FLUSH yes yes yes no -TAG_FUA yes yes yes yes - - -QUEUE_ORDERED_NONE - I/O barriers are not needed and/or supported. - - Sequence: N/A - -QUEUE_ORDERED_DRAIN - Requests are ordered by draining the request queue and cache - flushing isn't needed. - - Sequence: drain => barrier - -QUEUE_ORDERED_DRAIN_FLUSH - Requests are ordered by draining the request queue and both - pre-barrier and post-barrier cache flushings are needed. - - Sequence: drain => preflush => barrier => postflush - -QUEUE_ORDERED_DRAIN_FUA - Requests are ordered by draining the request queue and - pre-barrier cache flushing is needed. By using FUA on barrier - request, post-barrier flushing can be skipped. - - Sequence: drain => preflush => barrier - -QUEUE_ORDERED_TAG - Requests are ordered by ordered tag and cache flushing isn't - needed. - - Sequence: barrier - -QUEUE_ORDERED_TAG_FLUSH - Requests are ordered by ordered tag and both pre-barrier and - post-barrier cache flushings are needed. - - Sequence: preflush -> barrier -> postflush - -QUEUE_ORDERED_TAG_FUA - Requests are ordered by ordered tag and pre-barrier cache - flushing is needed. By using FUA on barrier request, - post-barrier flushing can be skipped. - - Sequence: preflush -> barrier - - -Random notes/caveats --------------------- - -* SCSI layer currently can't use TAG ordering even if the drive, -controller and driver support it. The problem is that SCSI midlayer -request dispatch function is not atomic. It releases queue lock and -switch to SCSI host lock during issue and it's possible and likely to -happen in time that requests change their relative positions. Once -this problem is solved, TAG ordering can be enabled. - -* Currently, no matter which ordered mode is used, there can be only -one barrier request in progress. All I/O barriers are held off by -block layer until the previous I/O barrier is complete. This doesn't -make any difference for DRAIN ordered devices, but, for TAG ordered -devices with very high command latency, passing multiple I/O barriers -to low level *might* be helpful if they are very frequent. Well, this -certainly is a non-issue. I'm writing this just to make clear that no -two I/O barrier is ever passed to low-level driver. - -* Completion order. Requests in ordered sequence are issued in order -but not required to finish in order. Barrier implementation can -handle out-of-order completion of ordered sequence. IOW, the requests -MUST be processed in order but the hardware/software completion paths -are allowed to reorder completion notifications - eg. current SCSI -midlayer doesn't preserve completion order during error handling. - -* Requeueing order. Low-level drivers are free to requeue any request -after they removed it from the request queue with -blkdev_dequeue_request(). As barrier sequence should be kept in order -when requeued, generic elevator code takes care of putting requests in -order around barrier. See blk_ordered_req_seq() and -ELEVATOR_INSERT_REQUEUE handling in __elv_add_request() for details. - -Note that block drivers must not requeue preceding requests while -completing latter requests in an ordered sequence. Currently, no -error checking is done against this. - -* Error handling. Currently, block layer will report error to upper -layer if any of requests in an ordered sequence fails. Unfortunately, -this doesn't seem to be enough. Look at the following request flow. -QUEUE_ORDERED_TAG_FLUSH is in use. - - [0] [1] [2] [3] [pre] [barrier] [post] < [4] [5] [6] ... > - still in elevator - -Let's say request [2], [3] are write requests to update file system -metadata (journal or whatever) and [barrier] is used to mark that -those updates are valid. Consider the following sequence. - - i. Requests [0] ~ [post] leaves the request queue and enters - low-level driver. - ii. After a while, unfortunately, something goes wrong and the - drive fails [2]. Note that any of [0], [1] and [3] could have - completed by this time, but [pre] couldn't have been finished - as the drive must process it in order and it failed before - processing that command. - iii. Error handling kicks in and determines that the error is - unrecoverable and fails [2], and resumes operation. - iv. [pre] [barrier] [post] gets processed. - v. *BOOM* power fails - -The problem here is that the barrier request is *supposed* to indicate -that filesystem update requests [2] and [3] made it safely to the -physical medium and, if the machine crashes after the barrier is -written, filesystem recovery code can depend on that. Sadly, that -isn't true in this case anymore. IOW, the success of a I/O barrier -should also be dependent on success of some of the preceding requests, -where only upper layer (filesystem) knows what 'some' is. - -This can be solved by implementing a way to tell the block layer which -requests affect the success of the following barrier request and -making lower lever drivers to resume operation on error only after -block layer tells it to do so. - -As the probability of this happening is very low and the drive should -be faulty, implementing the fix is probably an overkill. But, still, -it's there. - -* In previous drafts of barrier implementation, there was fallback -mechanism such that, if FUA or ordered TAG fails, less fancy ordered -mode can be selected and the failed barrier request is retried -automatically. The rationale for this feature was that as FUA is -pretty new in ATA world and ordered tag was never used widely, there -could be devices which report to support those features but choke when -actually given such requests. - - This was removed for two reasons 1. it's an overkill 2. it's -impossible to implement properly when TAG ordering is used as low -level drivers resume after an error automatically. If it's ever -needed adding it back and modifying low level drivers accordingly -shouldn't be difficult. diff --git a/Documentation/block/writeback_cache_control.txt b/Documentation/block/writeback_cache_control.txt new file mode 100644 index 000000000000..83407d36630a --- /dev/null +++ b/Documentation/block/writeback_cache_control.txt @@ -0,0 +1,86 @@ + +Explicit volatile write back cache control +===================================== + +Introduction +------------ + +Many storage devices, especially in the consumer market, come with volatile +write back caches. That means the devices signal I/O completion to the +operating system before data actually has hit the non-volatile storage. This +behavior obviously speeds up various workloads, but it means the operating +system needs to force data out to the non-volatile storage when it performs +a data integrity operation like fsync, sync or an unmount. + +The Linux block layer provides two simple mechanisms that let filesystems +control the caching behavior of the storage device. These mechanisms are +a forced cache flush, and the Force Unit Access (FUA) flag for requests. + + +Explicit cache flushes +---------------------- + +The REQ_FLUSH flag can be OR ed into the r/w flags of a bio submitted from +the filesystem and will make sure the volatile cache of the storage device +has been flushed before the actual I/O operation is started. This explicitly +guarantees that previously completed write requests are on non-volatile +storage before the flagged bio starts. In addition the REQ_FLUSH flag can be +set on an otherwise empty bio structure, which causes only an explicit cache +flush without any dependent I/O. It is recommend to use +the blkdev_issue_flush() helper for a pure cache flush. + + +Forced Unit Access +----------------- + +The REQ_FUA flag can be OR ed into the r/w flags of a bio submitted from the +filesystem and will make sure that I/O completion for this request is only +signaled after the data has been committed to non-volatile storage. + + +Implementation details for filesystems +-------------------------------------- + +Filesystems can simply set the REQ_FLUSH and REQ_FUA bits and do not have to +worry if the underlying devices need any explicit cache flushing and how +the Forced Unit Access is implemented. The REQ_FLUSH and REQ_FUA flags +may both be set on a single bio. + + +Implementation details for make_request_fn based block drivers +-------------------------------------------------------------- + +These drivers will always see the REQ_FLUSH and REQ_FUA bits as they sit +directly below the submit_bio interface. For remapping drivers the REQ_FUA +bits need to be propagated to underlying devices, and a global flush needs +to be implemented for bios with the REQ_FLUSH bit set. For real device +drivers that do not have a volatile cache the REQ_FLUSH and REQ_FUA bits +on non-empty bios can simply be ignored, and REQ_FLUSH requests without +data can be completed successfully without doing any work. Drivers for +devices with volatile caches need to implement the support for these +flags themselves without any help from the block layer. + + +Implementation details for request_fn based block drivers +-------------------------------------------------------------- + +For devices that do not support volatile write caches there is no driver +support required, the block layer completes empty REQ_FLUSH requests before +entering the driver and strips off the REQ_FLUSH and REQ_FUA bits from +requests that have a payload. For devices with volatile write caches the +driver needs to tell the block layer that it supports flushing caches by +doing: + + blk_queue_flush(sdkp->disk->queue, REQ_FLUSH); + +and handle empty REQ_FLUSH requests in its prep_fn/request_fn. Note that +REQ_FLUSH requests with a payload are automatically turned into a sequence +of an empty REQ_FLUSH request followed by the actual write by the block +layer. For devices that also support the FUA bit the block layer needs +to be told to pass through the REQ_FUA bit using: + + blk_queue_flush(sdkp->disk->queue, REQ_FLUSH | REQ_FUA); + +and the driver must handle write requests that have the REQ_FUA bit set +in prep_fn/request_fn. If the FUA bit is not natively supported the block +layer turns it into an empty REQ_FLUSH request after the actual write. diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt index 6919d62591d9..d6da611f8f63 100644 --- a/Documentation/cgroups/blkio-controller.txt +++ b/Documentation/cgroups/blkio-controller.txt @@ -8,12 +8,17 @@ both at leaf nodes as well as at intermediate nodes in a storage hierarchy. Plan is to use the same cgroup based management interface for blkio controller and based on user options switch IO policies in the background. -In the first phase, this patchset implements proportional weight time based -division of disk policy. It is implemented in CFQ. Hence this policy takes -effect only on leaf nodes when CFQ is being used. +Currently two IO control policies are implemented. First one is proportional +weight time based division of disk policy. It is implemented in CFQ. Hence +this policy takes effect only on leaf nodes when CFQ is being used. The second +one is throttling policy which can be used to specify upper IO rate limits +on devices. This policy is implemented in generic block layer and can be +used on leaf nodes as well as higher level logical devices like device mapper. HOWTO ===== +Proportional Weight division of bandwidth +----------------------------------------- You can do a very simple testing of running two dd threads in two different cgroups. Here is what you can do. @@ -55,6 +60,35 @@ cgroups. Here is what you can do. group dispatched to the disk. We provide fairness in terms of disk time, so ideally io.disk_time of cgroups should be in proportion to the weight. +Throttling/Upper Limit policy +----------------------------- +- Enable Block IO controller + CONFIG_BLK_CGROUP=y + +- Enable throttling in block layer + CONFIG_BLK_DEV_THROTTLING=y + +- Mount blkio controller + mount -t cgroup -o blkio none /cgroup/blkio + +- Specify a bandwidth rate on particular device for root group. The format + for policy is "<major>:<minor> <byes_per_second>". + + echo "8:16 1048576" > /cgroup/blkio/blkio.read_bps_device + + Above will put a limit of 1MB/second on reads happening for root group + on device having major/minor number 8:16. + +- Run dd to read a file and see if rate is throttled to 1MB/s or not. + + # dd if=/mnt/common/zerofile of=/dev/null bs=4K count=1024 + # iflag=direct + 1024+0 records in + 1024+0 records out + 4194304 bytes (4.2 MB) copied, 4.0001 s, 1.0 MB/s + + Limits for writes can be put using blkio.write_bps_device file. + Various user visible config options =================================== CONFIG_BLK_CGROUP @@ -68,8 +102,13 @@ CONFIG_CFQ_GROUP_IOSCHED - Enables group scheduling in CFQ. Currently only 1 level of group creation is allowed. +CONFIG_BLK_DEV_THROTTLING + - Enable block device throttling support in block layer. + Details of cgroup files ======================= +Proportional weight policy files +-------------------------------- - blkio.weight - Specifies per cgroup weight. This is default weight of the group on all the devices until and unless overridden by per device rule. @@ -210,6 +249,67 @@ Details of cgroup files and minor number of the device and third field specifies the number of times a group was dequeued from a particular device. +Throttling/Upper limit policy files +----------------------------------- +- blkio.throttle.read_bps_device + - Specifies upper limit on READ rate from the device. IO rate is + specified in bytes per second. Rules are per deivce. Following is + the format. + + echo "<major>:<minor> <rate_bytes_per_second>" > /cgrp/blkio.read_bps_device + +- blkio.throttle.write_bps_device + - Specifies upper limit on WRITE rate to the device. IO rate is + specified in bytes per second. Rules are per deivce. Following is + the format. + + echo "<major>:<minor> <rate_bytes_per_second>" > /cgrp/blkio.write_bps_device + +- blkio.throttle.read_iops_device + - Specifies upper limit on READ rate from the device. IO rate is + specified in IO per second. Rules are per deivce. Following is + the format. + + echo "<major>:<minor> <rate_io_per_second>" > /cgrp/blkio.read_iops_device + +- blkio.throttle.write_iops_device + - Specifies upper limit on WRITE rate to the device. IO rate is + specified in io per second. Rules are per deivce. Following is + the format. + + echo "<major>:<minor> <rate_io_per_second>" > /cgrp/blkio.write_iops_device + +Note: If both BW and IOPS rules are specified for a device, then IO is + subjectd to both the constraints. + +- blkio.throttle.io_serviced + - Number of IOs (bio) completed to/from the disk by the group (as + seen by throttling policy). These are further divided by the type + of operation - read or write, sync or async. First two fields specify + the major and minor number of the device, third field specifies the + operation type and the fourth field specifies the number of IOs. + + blkio.io_serviced does accounting as seen by CFQ and counts are in + number of requests (struct request). On the other hand, + blkio.throttle.io_serviced counts number of IO in terms of number + of bios as seen by throttling policy. These bios can later be + merged by elevator and total number of requests completed can be + lesser. + +- blkio.throttle.io_service_bytes + - Number of bytes transferred to/from the disk by the group. These + are further divided by the type of operation - read or write, sync + or async. First two fields specify the major and minor number of the + device, third field specifies the operation type and the fourth field + specifies the number of bytes. + + These numbers should roughly be same as blkio.io_service_bytes as + updated by CFQ. The difference between two is that + blkio.io_service_bytes will not be updated if CFQ is not operating + on request queue. + +Common files among various policies +----------------------------------- - blkio.reset_stats - Writing an int to this file will result in resetting all the stats for that cgroup. diff --git a/Documentation/devices.txt b/Documentation/devices.txt index d0d1df6cb5de..c58abf1ccc71 100644 --- a/Documentation/devices.txt +++ b/Documentation/devices.txt @@ -239,6 +239,7 @@ Your cooperation is appreciated. 0 = /dev/tty Current TTY device 1 = /dev/console System console 2 = /dev/ptmx PTY master multiplex + 3 = /dev/ttyprintk User messages via printk TTY device 64 = /dev/cua0 Callout device for ttyS0 ... 255 = /dev/cua191 Callout device for ttyS191 @@ -2553,7 +2554,10 @@ Your cooperation is appreciated. 175 = /dev/usb/legousbtower15 16th USB Legotower device 176 = /dev/usb/usbtmc1 First USB TMC device ... - 192 = /dev/usb/usbtmc16 16th USB TMC device + 191 = /dev/usb/usbtmc16 16th USB TMC device + 192 = /dev/usb/yurex1 First USB Yurex device + ... + 209 = /dev/usb/yurex16 16th USB Yurex device 240 = /dev/usb/dabusb0 First daubusb device ... 243 = /dev/usb/dabusb3 Fourth dabusb device diff --git a/Documentation/dynamic-debug-howto.txt b/Documentation/dynamic-debug-howto.txt index 674c5663d346..58ea64a96165 100644 --- a/Documentation/dynamic-debug-howto.txt +++ b/Documentation/dynamic-debug-howto.txt @@ -24,7 +24,7 @@ Dynamic debug has even more useful features: read to display the complete list of known debug statements, to help guide you Controlling dynamic debug Behaviour -=============================== +=================================== The behaviour of pr_debug()/dev_debug()s are controlled via writing to a control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs @@ -212,6 +212,26 @@ Note the regexp ^[-+=][scp]+$ matches a flags specification. Note also that there is no convenient syntax to remove all the flags at once, you need to use "-psc". + +Debug messages during boot process +================================== + +To be able to activate debug messages during the boot process, +even before userspace and debugfs exists, use the boot parameter: +ddebug_query="QUERY" + +QUERY follows the syntax described above, but must not exceed 1023 +characters. The enablement of debug messages is done as an arch_initcall. +Thus you can enable debug messages in all code processed after this +arch_initcall via this boot parameter. +On an x86 system for example ACPI enablement is a subsys_initcall and +ddebug_query="file ec.c +p" +will show early Embedded Controller transactions during ACPI setup if +your machine (typically a laptop) has an Embedded Controller. +PCI (or other devices) initialization also is a hot candidate for using +this boot parameter for debugging purposes. + + Examples ======== diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 5e2bc4ab897a..d2af87ba96e1 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -502,16 +502,6 @@ Who: Thomas Gleixner <tglx@linutronix.de> ---------------------------- -What: old ieee1394 subsystem (CONFIG_IEEE1394) -When: 2.6.37 -Files: drivers/ieee1394/ except init_ohci1394_dma.c -Why: superseded by drivers/firewire/ (CONFIG_FIREWIRE) which offers more - features, better performance, and better security, all with smaller - and more modern code base -Who: Stefan Richter <stefanr@s5r6.in-berlin.de> - ----------------------------- - What: The acpi_sleep=s4_nonvs command line option When: 2.6.37 Files: arch/x86/kernel/acpi/sleep.c @@ -536,3 +526,22 @@ Who: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> ---------------------------- +What: iwlwifi disable_hw_scan module parameters +When: 2.6.40 +Why: Hareware scan is the prefer method for iwlwifi devices for + scanning operation. Remove software scan support for all the + iwlwifi devices. + +Who: Wey-Yi Guy <wey-yi.w.guy@intel.com> + +---------------------------- + +What: access to nfsd auth cache through sys_nfsservctl or '.' files + in the 'nfsd' filesystem. +When: 2.6.40 +Why: This is a legacy interface which have been replaced by a more + dynamic cache. Continuing to maintain this interface is an + unnecessary burden. +Who: NeilBrown <neilb@suse.de> + +---------------------------- diff --git a/Documentation/filesystems/nfs/00-INDEX b/Documentation/filesystems/nfs/00-INDEX index 2f68cd688769..a57e12411d2a 100644 --- a/Documentation/filesystems/nfs/00-INDEX +++ b/Documentation/filesystems/nfs/00-INDEX @@ -12,5 +12,9 @@ nfs-rdma.txt - how to install and setup the Linux NFS/RDMA client and server software nfsroot.txt - short guide on setting up a diskless box with NFS root filesystem. +pnfs.txt + - short explanation of some of the internals of the pnfs client code rpc-cache.txt - introduction to the caching mechanisms in the sunrpc layer. +idmapper.txt + - information for configuring request-keys to be used by idmapper diff --git a/Documentation/filesystems/nfs/idmapper.txt b/Documentation/filesystems/nfs/idmapper.txt new file mode 100644 index 000000000000..c3852041a21f --- /dev/null +++ b/Documentation/filesystems/nfs/idmapper.txt @@ -0,0 +1,67 @@ + +========= +ID Mapper +========= +Id mapper is used by NFS to translate user and group ids into names, and to +translate user and group names into ids. Part of this translation involves +performing an upcall to userspace to request the information. Id mapper will +user request-key to perform this upcall and cache the result. The program +/usr/sbin/nfs.upcall should be called by request-key, and will perform the +translation and initialize a key with the resulting information. + + NFS_USE_NEW_IDMAPPER must be selected when configuring the kernel to use this + feature. + +=========== +Configuring +=========== +The file /etc/request-key.conf will need to be modified so /sbin/request-key can +direct the upcall. The following line should be added: + +#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ... +#====== ======= =============== =============== =============================== +create id_resolver * * /usr/sbin/nfs.upcall %k %d 600 + +This will direct all id_resolver requests to the program /usr/sbin/nfs.upcall. +The last parameter, 600, defines how many seconds into the future the key will +expire. This parameter is optional for /usr/sbin/nfs.upcall. When the timeout +is not specified, nfs.upcall will default to 600 seconds. + +id mapper uses for key descriptions: + uid: Find the UID for the given user + gid: Find the GID for the given group + user: Find the user name for the given UID + group: Find the group name for the given GID + +You can handle any of these individually, rather than using the generic upcall +program. If you would like to use your own program for a uid lookup then you +would edit your request-key.conf so it look similar to this: + +#OP TYPE DESCRIPTION CALLOUT INFO PROGRAM ARG1 ARG2 ARG3 ... +#====== ======= =============== =============== =============================== +create id_resolver uid:* * /some/other/program %k %d 600 +create id_resolver * * /usr/sbin/nfs.upcall %k %d 600 + +Notice that the new line was added above the line for the generic program. +request-key will find the first matching line and corresponding program. In +this case, /some/other/program will handle all uid lookups and +/usr/sbin/nfs.upcall will handle gid, user, and group lookups. + +See <file:Documentation/keys-request-keys.txt> for more information about the +request-key function. + + +========== +nfs.upcall +========== +nfs.upcall is designed to be called by request-key, and should not be run "by +hand". This program takes two arguments, a serialized key and a key +description. The serialized key is first converted into a key_serial_t, and +then passed as an argument to keyctl_instantiate (both are part of keyutils.h). + +The actual lookups are performed by functions found in nfsidmap.h. nfs.upcall +determines the correct function to call by looking at the first part of the +description string. For example, a uid lookup description will appear as +"uid:user@domain". + +nfs.upcall will return 0 if the key was instantiated, and non-zero otherwise. diff --git a/Documentation/filesystems/nfs/nfsroot.txt b/Documentation/filesystems/nfs/nfsroot.txt index f2430a7974e1..90c71c6f0d00 100644 --- a/Documentation/filesystems/nfs/nfsroot.txt +++ b/Documentation/filesystems/nfs/nfsroot.txt @@ -159,6 +159,28 @@ ip=<client-ip>:<server-ip>:<gw-ip>:<netmask>:<hostname>:<device>:<autoconf> Default: any +nfsrootdebug + + This parameter enables debugging messages to appear in the kernel + log at boot time so that administrators can verify that the correct + NFS mount options, server address, and root path are passed to the + NFS client. + + +rdinit=<executable file> + + To specify which file contains the program that starts system + initialization, administrators can use this command line parameter. + The default value of this parameter is "/init". If the specified + file exists and the kernel can execute it, root filesystem related + kernel command line parameters, including `nfsroot=', are ignored. + + A description of the process of mounting the root file system can be + found in: + + Documentation/early-userspace/README + + 3.) Boot Loader diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt new file mode 100644 index 000000000000..bc0b9cfe095b --- /dev/null +++ b/Documentation/filesystems/nfs/pnfs.txt @@ -0,0 +1,48 @@ +Reference counting in pnfs: +========================== + +The are several inter-related caches. We have layouts which can +reference multiple devices, each of which can reference multiple data servers. +Each data server can be referenced by multiple devices. Each device +can be referenced by multiple layouts. To keep all of this straight, +we need to reference count. + + +struct pnfs_layout_hdr +---------------------- +The on-the-wire command LAYOUTGET corresponds to struct +pnfs_layout_segment, usually referred to by the variable name lseg. +Each nfs_inode may hold a pointer to a cache of of these layout +segments in nfsi->layout, of type struct pnfs_layout_hdr. + +We reference the header for the inode pointing to it, across each +outstanding RPC call that references it (LAYOUTGET, LAYOUTRETURN, +LAYOUTCOMMIT), and for each lseg held within. + +Each header is also (when non-empty) put on a list associated with +struct nfs_client (cl_layouts). Being put on this list does not bump +the reference count, as the layout is kept around by the lseg that +keeps it in the list. + +deviceid_cache +-------------- +lsegs reference device ids, which are resolved per nfs_client and +layout driver type. The device ids are held in a RCU cache (struct +nfs4_deviceid_cache). The cache itself is referenced across each +mount. The entries (struct nfs4_deviceid) themselves are held across +the lifetime of each lseg referencing them. + +RCU is used because the deviceid is basically a write once, read many +data structure. The hlist size of 32 buckets needs better +justification, but seems reasonable given that we can have multiple +deviceid's per filesystem, and multiple filesystems per nfs_client. + +The hash code is copied from the nfsd code base. A discussion of +hashing and variations of this algorithm can be found at: +http://groups.google.com/group/comp.lang.c/browse_thread/thread/9522965e2b8d3809 + +data server cache +----------------- +file driver devices refer to data servers, which are kept in a module +level cache. Its reference is held over the lifetime of the deviceid +pointing to it. diff --git a/Documentation/hwmon/ltc4261 b/Documentation/hwmon/ltc4261 new file mode 100644 index 000000000000..eba2e2c4b94d --- /dev/null +++ b/Documentation/hwmon/ltc4261 @@ -0,0 +1,63 @@ +Kernel driver ltc4261 +===================== + +Supported chips: + * Linear Technology LTC4261 + Prefix: 'ltc4261' + Addresses scanned: - + Datasheet: + http://cds.linear.com/docs/Datasheet/42612fb.pdf + +Author: Guenter Roeck <guenter.roeck@ericsson.com> + + +Description +----------- + +The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board +to be safely inserted and removed from a live backplane. + + +Usage Notes +----------- + +This driver does not probe for LTC4261 devices, since there is no register +which can be safely used to identify the chip. You will have to instantiate +the devices explicitly. + +Example: the following will load the driver for an LTC4261 at address 0x10 +on I2C bus #1: +$ modprobe ltc4261 +$ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device + + +Sysfs entries +------------- + +Voltage readings provided by this driver are reported as obtained from the ADC +registers. If a set of voltage divider resistors is installed, calculate the +real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the +value of the divider resistor against the measured voltage and R2 is the value +of the divider resistor against Ground. + +Current reading provided by this driver is reported as obtained from the ADC +Current Sense register. The reported value assumes that a 1 mOhm sense resistor +is installed. If a different sense resistor is installed, calculate the real +current by dividing the reported value by the sense resistor value in mOhm. + +The chip has two voltage sensors, but only one set of voltage alarm status bits. +In many many designs, those alarms are associated with the ADIN2 sensor, due to +the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available +on all chip variants. To ensure that the alarm condition is reported to the user, +report it with both voltage sensors. + +in1_input ADIN2 voltage (mV) +in1_min_alarm ADIN/ADIN2 Undervoltage alarm +in1_max_alarm ADIN/ADIN2 Overvoltage alarm + +in2_input ADIN voltage (mV) +in2_min_alarm ADIN/ADIN2 Undervoltage alarm +in2_max_alarm ADIN/ADIN2 Overvoltage alarm + +curr1_input SENSE current (mA) +curr1_alarm SENSE overcurrent alarm diff --git a/Documentation/input/ntrig.txt b/Documentation/input/ntrig.txt new file mode 100644 index 000000000000..be1fd981f73f --- /dev/null +++ b/Documentation/input/ntrig.txt @@ -0,0 +1,126 @@ +N-Trig touchscreen Driver +------------------------- + Copyright (c) 2008-2010 Rafi Rubin <rafi@seas.upenn.edu> + Copyright (c) 2009-2010 Stephane Chatty + +This driver provides support for N-Trig pen and multi-touch sensors. Single +and multi-touch events are translated to the appropriate protocols for +the hid and input systems. Pen events are sufficiently hid compliant and +are left to the hid core. The driver also provides additional filtering +and utility functions accessible with sysfs and module parameters. + +This driver has been reported to work properly with multiple N-Trig devices +attached. + + +Parameters +---------- + +Note: values set at load time are global and will apply to all applicable +devices. Adjusting parameters with sysfs will override the load time values, +but only for that one device. + +The following parameters are used to configure filters to reduce noise: + +activate_slack number of fingers to ignore before processing events + +activation_height size threshold to activate immediately +activation_width + +min_height size threshold bellow which fingers are ignored +min_width both to decide activation and during activity + +deactivate_slack the number of "no contact" frames to ignore before + propagating the end of activity events + +When the last finger is removed from the device, it sends a number of empty +frames. By holding off on deactivation for a few frames we can tolerate false +erroneous disconnects, where the sensor may mistakenly not detect a finger that +is still present. Thus deactivate_slack addresses problems where a users might +see breaks in lines during drawing, or drop an object during a long drag. + + +Additional sysfs items +---------------------- + +These nodes just provide easy access to the ranges reported by the device. +sensor_logical_height the range for positions reported during activity +sensor_logical_width + +sensor_physical_height internal ranges not used for normal events but +sensor_physical_width useful for tuning + +All N-Trig devices with product id of 1 report events in the ranges of +X: 0-9600 +Y: 0-7200 +However not all of these devices have the same physical dimensions. Most +seem to be 12" sensors (Dell Latitude XT and XT2 and the HP TX2), and +at least one model (Dell Studio 17) has a 17" sensor. The ratio of physical +to logical sizes is used to adjust the size based filter parameters. + + +Filtering +--------- + +With the release of the early multi-touch firmwares it became increasingly +obvious that these sensors were prone to erroneous events. Users reported +seeing both inappropriately dropped contact and ghosts, contacts reported +where no finger was actually touching the screen. + +Deactivation slack helps prevent dropped contact for single touch use, but does +not address the problem of dropping one of more contacts while other contacts +are still active. Drops in the multi-touch context require additional +processing and should be handled in tandem with tacking. + +As observed ghost contacts are similar to actual use of the sensor, but they +seem to have different profiles. Ghost activity typically shows up as small +short lived touches. As such, I assume that the longer the continuous stream +of events the more likely those events are from a real contact, and that the +larger the size of each contact the more likely it is real. Balancing the +goals of preventing ghosts and accepting real events quickly (to minimize +user observable latency), the filter accumulates confidence for incoming +events until it hits thresholds and begins propagating. In the interest in +minimizing stored state as well as the cost of operations to make a decision, +I've kept that decision simple. + +Time is measured in terms of the number of fingers reported, not frames since +the probability of multiple simultaneous ghosts is expected to drop off +dramatically with increasing numbers. Rather than accumulate weight as a +function of size, I just use it as a binary threshold. A sufficiently large +contact immediately overrides the waiting period and leads to activation. + +Setting the activation size thresholds to large values will result in deciding +primarily on activation slack. If you see longer lived ghosts, turning up the +activation slack while reducing the size thresholds may suffice to eliminate +the ghosts while keeping the screen quite responsive to firm taps. + +Contacts continue to be filtered with min_height and min_width even after +the initial activation filter is satisfied. The intent is to provide +a mechanism for filtering out ghosts in the form of an extra finger while +you actually are using the screen. In practice this sort of ghost has +been far less problematic or relatively rare and I've left the defaults +set to 0 for both parameters, effectively turning off that filter. + +I don't know what the optimal values are for these filters. If the defaults +don't work for you, please play with the parameters. If you do find other +values more comfortable, I would appreciate feedback. + +The calibration of these devices does drift over time. If ghosts or contact +dropping worsen and interfere with the normal usage of your device, try +recalibrating it. + + +Calibration +----------- + +The N-Trig windows tools provide calibration and testing routines. Also an +unofficial unsupported set of user space tools including a calibrator is +available at: +http://code.launchpad.net/~rafi-seas/+junk/ntrig_calib + + +Tracking +-------- + +As of yet, all tested N-Trig firmwares do not track fingers. When multiple +contacts are active they seem to be sorted primarily by Y position. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 02f21d9220ce..4bc2f3c3da5b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -43,10 +43,11 @@ parameter is applicable: AVR32 AVR32 architecture is enabled. AX25 Appropriate AX.25 support is enabled. BLACKFIN Blackfin architecture is enabled. - DRM Direct Rendering Management support is enabled. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled EFI EFI Partitioning (GPT) is enabled EIDE EIDE/ATAPI support is enabled. + DRM Direct Rendering Management support is enabled. + DYNAMIC_DEBUG Build in debug messages and enable them at runtime FB The frame buffer device is enabled. GCOV GCOV profiling is enabled. HW Appropriate hardware is enabled. @@ -570,6 +571,10 @@ and is between 256 and 4096 characters. It is defined in the file Format: <port#>,<type> See also Documentation/input/joystick-parport.txt + ddebug_query= [KNL,DYNAMIC_DEBUG] Enable debug messages at early boot + time. See Documentation/dynamic-debug-howto.txt for + details. + debug [KNL] Enable kernel debugging (events log level). debug_locks_verbose= @@ -1126,9 +1131,13 @@ and is between 256 and 4096 characters. It is defined in the file kvm.oos_shadow= [KVM] Disable out-of-sync shadow paging. Default is 1 (enabled) - kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. + kvm.mmu_audit= [KVM] This is a R/W parameter which allows audit + KVM MMU at runtime. Default is 0 (off) + kvm-amd.nested= [KVM,AMD] Allow nested virtualization in KVM/SVM. + Default is 1 (enabled) + kvm-amd.npt= [KVM,AMD] Disable nested paging (virtualized MMU) for all guests. Default is 1 (enabled) if in 64bit or 32bit-PAE mode @@ -1532,12 +1541,15 @@ and is between 256 and 4096 characters. It is defined in the file 1 to enable accounting Default value is 0. - nfsaddrs= [NFS] + nfsaddrs= [NFS] Deprecated. Use ip= instead. See Documentation/filesystems/nfs/nfsroot.txt. nfsroot= [NFS] nfs root filesystem for disk-less boxes. See Documentation/filesystems/nfs/nfsroot.txt. + nfsrootdebug [NFS] enable nfsroot debugging messages. + See Documentation/filesystems/nfs/nfsroot.txt. + nfs.callback_tcpport= [NFS] set the TCP port on which the NFSv4 callback channel should listen. @@ -1693,6 +1705,8 @@ and is between 256 and 4096 characters. It is defined in the file nojitter [IA64] Disables jitter checking for ITC timers. + no-kvmclock [X86,KVM] Disable paravirtualized KVM clock driver + nolapic [X86-32,APIC] Do not enable or use the local APIC. nolapic_timer [X86-32,APIC] Do not use the local APIC timer. @@ -1713,7 +1727,7 @@ and is between 256 and 4096 characters. It is defined in the file norandmaps Don't use address space randomization. Equivalent to echo 0 > /proc/sys/kernel/randomize_va_space - noreplace-paravirt [X86-32,PV_OPS] Don't patch paravirt_ops + noreplace-paravirt [X86,IA-64,PV_OPS] Don't patch paravirt_ops noreplace-smp [X86-32,SMP] Don't replace SMP instructions with UP alternatives @@ -2370,6 +2384,15 @@ and is between 256 and 4096 characters. It is defined in the file switches= [HW,M68k] + sysfs.deprecated=0|1 [KNL] + Enable/disable old style sysfs layout for old udev + on older distributions. When this option is enabled + very new udev will not work anymore. When this option + is disabled (or CONFIG_SYSFS_DEPRECATED not compiled) + in older udev will not work anymore. + Default depends on CONFIG_SYSFS_DEPRECATED_V2 set in + the kernel configuration. + sysrq_always_enabled [KNL] Ignore sysrq setting - this boot parameter will @@ -2418,7 +2441,7 @@ and is between 256 and 4096 characters. It is defined in the file topology informations if the hardware supports these. The scheduler will make use of these informations and e.g. base its process migration decisions on it. - Default is off. + Default is on. tp720= [HW,PS2] diff --git a/Documentation/kvm/api.txt b/Documentation/kvm/api.txt index 5f5b64982b1a..b336266bea5e 100644 --- a/Documentation/kvm/api.txt +++ b/Documentation/kvm/api.txt @@ -320,13 +320,13 @@ struct kvm_translation { 4.15 KVM_INTERRUPT Capability: basic -Architectures: x86 +Architectures: x86, ppc Type: vcpu ioctl Parameters: struct kvm_interrupt (in) Returns: 0 on success, -1 on error Queues a hardware interrupt vector to be injected. This is only -useful if in-kernel local APIC is not used. +useful if in-kernel local APIC or equivalent is not used. /* for KVM_INTERRUPT */ struct kvm_interrupt { @@ -334,8 +334,37 @@ struct kvm_interrupt { __u32 irq; }; +X86: + Note 'irq' is an interrupt vector, not an interrupt pin or line. +PPC: + +Queues an external interrupt to be injected. This ioctl is overleaded +with 3 different irq values: + +a) KVM_INTERRUPT_SET + + This injects an edge type external interrupt into the guest once it's ready + to receive interrupts. When injected, the interrupt is done. + +b) KVM_INTERRUPT_UNSET + + This unsets any pending interrupt. + + Only available with KVM_CAP_PPC_UNSET_IRQ. + +c) KVM_INTERRUPT_SET_LEVEL + + This injects a level type external interrupt into the guest context. The + interrupt stays pending until a specific ioctl with KVM_INTERRUPT_UNSET + is triggered. + + Only available with KVM_CAP_PPC_IRQ_LEVEL. + +Note that any value for 'irq' other than the ones stated above is invalid +and incurs unexpected behavior. + 4.16 KVM_DEBUG_GUEST Capability: basic @@ -1013,8 +1042,9 @@ number is just right, the 'nent' field is adjusted to the number of valid entries in the 'entries' array, which is then filled. The entries returned are the host cpuid as returned by the cpuid instruction, -with unknown or unsupported features masked out. The fields in each entry -are defined as follows: +with unknown or unsupported features masked out. Some features (for example, +x2apic), may not be present in the host cpu, but are exposed by kvm if it can +emulate them efficiently. The fields in each entry are defined as follows: function: the eax value used to obtain the entry index: the ecx value used to obtain the entry (for entries that are @@ -1032,6 +1062,29 @@ are defined as follows: eax, ebx, ecx, edx: the values returned by the cpuid instruction for this function/index combination +4.46 KVM_PPC_GET_PVINFO + +Capability: KVM_CAP_PPC_GET_PVINFO +Architectures: ppc +Type: vm ioctl +Parameters: struct kvm_ppc_pvinfo (out) +Returns: 0 on success, !0 on error + +struct kvm_ppc_pvinfo { + __u32 flags; + __u32 hcall[4]; + __u8 pad[108]; +}; + +This ioctl fetches PV specific information that need to be passed to the guest +using the device tree or other means from vm context. + +For now the only implemented piece of information distributed here is an array +of 4 instructions that make up a hypercall. + +If any additional field gets added to this structure later on, a bit for that +additional piece of information will be set in the flags bitmap. + 5. The kvm_run structure Application code obtains a pointer to the kvm_run structure by diff --git a/Documentation/kvm/ppc-pv.txt b/Documentation/kvm/ppc-pv.txt new file mode 100644 index 000000000000..a7f2244b3be9 --- /dev/null +++ b/Documentation/kvm/ppc-pv.txt @@ -0,0 +1,196 @@ +The PPC KVM paravirtual interface +================================= + +The basic execution principle by which KVM on PowerPC works is to run all kernel +space code in PR=1 which is user space. This way we trap all privileged +instructions and can emulate them accordingly. + +Unfortunately that is also the downfall. There are quite some privileged +instructions that needlessly return us to the hypervisor even though they +could be handled differently. + +This is what the PPC PV interface helps with. It takes privileged instructions +and transforms them into unprivileged ones with some help from the hypervisor. +This cuts down virtualization costs by about 50% on some of my benchmarks. + +The code for that interface can be found in arch/powerpc/kernel/kvm* + +Querying for existence +====================== + +To find out if we're running on KVM or not, we leverage the device tree. When +Linux is running on KVM, a node /hypervisor exists. That node contains a +compatible property with the value "linux,kvm". + +Once you determined you're running under a PV capable KVM, you can now use +hypercalls as described below. + +KVM hypercalls +============== + +Inside the device tree's /hypervisor node there's a property called +'hypercall-instructions'. This property contains at most 4 opcodes that make +up the hypercall. To call a hypercall, just call these instructions. + +The parameters are as follows: + + Register IN OUT + + r0 - volatile + r3 1st parameter Return code + r4 2nd parameter 1st output value + r5 3rd parameter 2nd output value + r6 4th parameter 3rd output value + r7 5th parameter 4th output value + r8 6th parameter 5th output value + r9 7th parameter 6th output value + r10 8th parameter 7th output value + r11 hypercall number 8th output value + r12 - volatile + +Hypercall definitions are shared in generic code, so the same hypercall numbers +apply for x86 and powerpc alike with the exception that each KVM hypercall +also needs to be ORed with the KVM vendor code which is (42 << 16). + +Return codes can be as follows: + + Code Meaning + + 0 Success + 12 Hypercall not implemented + <0 Error + +The magic page +============== + +To enable communication between the hypervisor and guest there is a new shared +page that contains parts of supervisor visible register state. The guest can +map this shared page using the KVM hypercall KVM_HC_PPC_MAP_MAGIC_PAGE. + +With this hypercall issued the guest always gets the magic page mapped at the +desired location in effective and physical address space. For now, we always +map the page to -4096. This way we can access it using absolute load and store +functions. The following instruction reads the first field of the magic page: + + ld rX, -4096(0) + +The interface is designed to be extensible should there be need later to add +additional registers to the magic page. If you add fields to the magic page, +also define a new hypercall feature to indicate that the host can give you more +registers. Only if the host supports the additional features, make use of them. + +The magic page has the following layout as described in +arch/powerpc/include/asm/kvm_para.h: + +struct kvm_vcpu_arch_shared { + __u64 scratch1; + __u64 scratch2; + __u64 scratch3; + __u64 critical; /* Guest may not get interrupts if == r1 */ + __u64 sprg0; + __u64 sprg1; + __u64 sprg2; + __u64 sprg3; + __u64 srr0; + __u64 srr1; + __u64 dar; + __u64 msr; + __u32 dsisr; + __u32 int_pending; /* Tells the guest if we have an interrupt */ +}; + +Additions to the page must only occur at the end. Struct fields are always 32 +or 64 bit aligned, depending on them being 32 or 64 bit wide respectively. + +Magic page features +=================== + +When mapping the magic page using the KVM hypercall KVM_HC_PPC_MAP_MAGIC_PAGE, +a second return value is passed to the guest. This second return value contains +a bitmap of available features inside the magic page. + +The following enhancements to the magic page are currently available: + + KVM_MAGIC_FEAT_SR Maps SR registers r/w in the magic page + +For enhanced features in the magic page, please check for the existence of the +feature before using them! + +MSR bits +======== + +The MSR contains bits that require hypervisor intervention and bits that do +not require direct hypervisor intervention because they only get interpreted +when entering the guest or don't have any impact on the hypervisor's behavior. + +The following bits are safe to be set inside the guest: + + MSR_EE + MSR_RI + MSR_CR + MSR_ME + +If any other bit changes in the MSR, please still use mtmsr(d). + +Patched instructions +==================== + +The "ld" and "std" instructions are transormed to "lwz" and "stw" instructions +respectively on 32 bit systems with an added offset of 4 to accomodate for big +endianness. + +The following is a list of mapping the Linux kernel performs when running as +guest. Implementing any of those mappings is optional, as the instruction traps +also act on the shared page. So calling privileged instructions still works as +before. + +From To +==== == + +mfmsr rX ld rX, magic_page->msr +mfsprg rX, 0 ld rX, magic_page->sprg0 +mfsprg rX, 1 ld rX, magic_page->sprg1 +mfsprg rX, 2 ld rX, magic_page->sprg2 +mfsprg rX, 3 ld rX, magic_page->sprg3 +mfsrr0 rX ld rX, magic_page->srr0 +mfsrr1 rX ld rX, magic_page->srr1 +mfdar rX ld rX, magic_page->dar +mfdsisr rX lwz rX, magic_page->dsisr + +mtmsr rX std rX, magic_page->msr +mtsprg 0, rX std rX, magic_page->sprg0 +mtsprg 1, rX std rX, magic_page->sprg1 +mtsprg 2, rX std rX, magic_page->sprg2 +mtsprg 3, rX std rX, magic_page->sprg3 +mtsrr0 rX std rX, magic_page->srr0 +mtsrr1 rX std rX, magic_page->srr1 +mtdar rX std rX, magic_page->dar +mtdsisr rX stw rX, magic_page->dsisr + +tlbsync nop + +mtmsrd rX, 0 b <special mtmsr section> +mtmsr rX b <special mtmsr section> + +mtmsrd rX, 1 b <special mtmsrd section> + +[Book3S only] +mtsrin rX, rY b <special mtsrin section> + +[BookE only] +wrteei [0|1] b <special wrteei section> + + +Some instructions require more logic to determine what's going on than a load +or store instruction can deliver. To enable patching of those, we keep some +RAM around where we can live translate instructions to. What happens is the +following: + + 1) copy emulation code to memory + 2) patch that code to fit the emulated instruction + 3) patch that code to return to the original pc + 4 + 4) patch the original instruction to branch to the new code + +That way we can inject an arbitrary amount of code as replacement for a single +instruction. This allows us to check for pending interrupts when setting EE=1 +for example. diff --git a/Documentation/kvm/timekeeping.txt b/Documentation/kvm/timekeeping.txt new file mode 100644 index 000000000000..0c5033a58c9e --- /dev/null +++ b/Documentation/kvm/timekeeping.txt @@ -0,0 +1,612 @@ + + Timekeeping Virtualization for X86-Based Architectures + + Zachary Amsden <zamsden@redhat.com> + Copyright (c) 2010, Red Hat. All rights reserved. + +1) Overview +2) Timing Devices +3) TSC Hardware +4) Virtualization Problems + +========================================================================= + +1) Overview + +One of the most complicated parts of the X86 platform, and specifically, +the virtualization of this platform is the plethora of timing devices available +and the complexity of emulating those devices. In addition, virtualization of +time introduces a new set of challenges because it introduces a multiplexed +division of time beyond the control of the guest CPU. + +First, we will describe the various timekeeping hardware available, then +present some of the problems which arise and solutions available, giving +specific recommendations for certain classes of KVM guests. + +The purpose of this document is to collect data and information relevant to +timekeeping which may be difficult to find elsewhere, specifically, +information relevant to KVM and hardware-based virtualization. + +========================================================================= + +2) Timing Devices + +First we discuss the basic hardware devices available. TSC and the related +KVM clock are special enough to warrant a full exposition and are described in +the following section. + +2.1) i8254 - PIT + +One of the first timer devices available is the programmable interrupt timer, +or PIT. The PIT has a fixed frequency 1.193182 MHz base clock and three +channels which can be programmed to deliver periodic or one-shot interrupts. +These three channels can be configured in different modes and have individual +counters. Channel 1 and 2 were not available for general use in the original +IBM PC, and historically were connected to control RAM refresh and the PC +speaker. Now the PIT is typically integrated as part of an emulated chipset +and a separate physical PIT is not used. + +The PIT uses I/O ports 0x40 - 0x43. Access to the 16-bit counters is done +using single or multiple byte access to the I/O ports. There are 6 modes +available, but not all modes are available to all timers, as only timer 2 +has a connected gate input, required for modes 1 and 5. The gate line is +controlled by port 61h, bit 0, as illustrated in the following diagram. + + -------------- ---------------- +| | | | +| 1.1932 MHz |---------->| CLOCK OUT | ---------> IRQ 0 +| Clock | | | | + -------------- | +->| GATE TIMER 0 | + | ---------------- + | + | ---------------- + | | | + |------>| CLOCK OUT | ---------> 66.3 KHZ DRAM + | | | (aka /dev/null) + | +->| GATE TIMER 1 | + | ---------------- + | + | ---------------- + | | | + |------>| CLOCK OUT | ---------> Port 61h, bit 5 + | | | +Port 61h, bit 0 ---------->| GATE TIMER 2 | \_.---- ____ + ---------------- _| )--|LPF|---Speaker + / *---- \___/ +Port 61h, bit 1 -----------------------------------/ + +The timer modes are now described. + +Mode 0: Single Timeout. This is a one-shot software timeout that counts down + when the gate is high (always true for timers 0 and 1). When the count + reaches zero, the output goes high. + +Mode 1: Triggered One-shot. The output is intially set high. When the gate + line is set high, a countdown is initiated (which does not stop if the gate is + lowered), during which the output is set low. When the count reaches zero, + the output goes high. + +Mode 2: Rate Generator. The output is initially set high. When the countdown + reaches 1, the output goes low for one count and then returns high. The value + is reloaded and the countdown automatically resumes. If the gate line goes + low, the count is halted. If the output is low when the gate is lowered, the + output automatically goes high (this only affects timer 2). + +Mode 3: Square Wave. This generates a high / low square wave. The count + determines the length of the pulse, which alternates between high and low + when zero is reached. The count only proceeds when gate is high and is + automatically reloaded on reaching zero. The count is decremented twice at + each clock to generate a full high / low cycle at the full periodic rate. + If the count is even, the clock remains high for N/2 counts and low for N/2 + counts; if the clock is odd, the clock is high for (N+1)/2 counts and low + for (N-1)/2 counts. Only even values are latched by the counter, so odd + values are not observed when reading. This is the intended mode for timer 2, + which generates sine-like tones by low-pass filtering the square wave output. + +Mode 4: Software Strobe. After programming this mode and loading the counter, + the output remains high until the counter reaches zero. Then the output + goes low for 1 clock cycle and returns high. The counter is not reloaded. + Counting only occurs when gate is high. + +Mode 5: Hardware Strobe. After programming and loading the counter, the + output remains high. When the gate is raised, a countdown is initiated + (which does not stop if the gate is lowered). When the counter reaches zero, + the output goes low for 1 clock cycle and then returns high. The counter is + not reloaded. + +In addition to normal binary counting, the PIT supports BCD counting. The +command port, 0x43 is used to set the counter and mode for each of the three +timers. + +PIT commands, issued to port 0x43, using the following bit encoding: + +Bit 7-4: Command (See table below) +Bit 3-1: Mode (000 = Mode 0, 101 = Mode 5, 11X = undefined) +Bit 0 : Binary (0) / BCD (1) + +Command table: + +0000 - Latch Timer 0 count for port 0x40 + sample and hold the count to be read in port 0x40; + additional commands ignored until counter is read; + mode bits ignored. + +0001 - Set Timer 0 LSB mode for port 0x40 + set timer to read LSB only and force MSB to zero; + mode bits set timer mode + +0010 - Set Timer 0 MSB mode for port 0x40 + set timer to read MSB only and force LSB to zero; + mode bits set timer mode + +0011 - Set Timer 0 16-bit mode for port 0x40 + set timer to read / write LSB first, then MSB; + mode bits set timer mode + +0100 - Latch Timer 1 count for port 0x41 - as described above +0101 - Set Timer 1 LSB mode for port 0x41 - as described above +0110 - Set Timer 1 MSB mode for port 0x41 - as described above +0111 - Set Timer 1 16-bit mode for port 0x41 - as described above + +1000 - Latch Timer 2 count for port 0x42 - as described above +1001 - Set Timer 2 LSB mode for port 0x42 - as described above +1010 - Set Timer 2 MSB mode for port 0x42 - as described above +1011 - Set Timer 2 16-bit mode for port 0x42 as described above + +1101 - General counter latch + Latch combination of counters into corresponding ports + Bit 3 = Counter 2 + Bit 2 = Counter 1 + Bit 1 = Counter 0 + Bit 0 = Unused + +1110 - Latch timer status + Latch combination of counter mode into corresponding ports + Bit 3 = Counter 2 + Bit 2 = Counter 1 + Bit 1 = Counter 0 + + The output of ports 0x40-0x42 following this command will be: + + Bit 7 = Output pin + Bit 6 = Count loaded (0 if timer has expired) + Bit 5-4 = Read / Write mode + 01 = MSB only + 10 = LSB only + 11 = LSB / MSB (16-bit) + Bit 3-1 = Mode + Bit 0 = Binary (0) / BCD mode (1) + +2.2) RTC + +The second device which was available in the original PC was the MC146818 real +time clock. The original device is now obsolete, and usually emulated by the +system chipset, sometimes by an HPET and some frankenstein IRQ routing. + +The RTC is accessed through CMOS variables, which uses an index register to +control which bytes are read. Since there is only one index register, read +of the CMOS and read of the RTC require lock protection (in addition, it is +dangerous to allow userspace utilities such as hwclock to have direct RTC +access, as they could corrupt kernel reads and writes of CMOS memory). + +The RTC generates an interrupt which is usually routed to IRQ 8. The interrupt +can function as a periodic timer, an additional once a day alarm, and can issue +interrupts after an update of the CMOS registers by the MC146818 is complete. +The type of interrupt is signalled in the RTC status registers. + +The RTC will update the current time fields by battery power even while the +system is off. The current time fields should not be read while an update is +in progress, as indicated in the status register. + +The clock uses a 32.768kHz crystal, so bits 6-4 of register A should be +programmed to a 32kHz divider if the RTC is to count seconds. + +This is the RAM map originally used for the RTC/CMOS: + +Location Size Description +------------------------------------------ +00h byte Current second (BCD) +01h byte Seconds alarm (BCD) +02h byte Current minute (BCD) +03h byte Minutes alarm (BCD) +04h byte Current hour (BCD) +05h byte Hours alarm (BCD) +06h byte Current day of week (BCD) +07h byte Current day of month (BCD) +08h byte Current month (BCD) +09h byte Current year (BCD) +0Ah byte Register A + bit 7 = Update in progress + bit 6-4 = Divider for clock + 000 = 4.194 MHz + 001 = 1.049 MHz + 010 = 32 kHz + 10X = test modes + 110 = reset / disable + 111 = reset / disable + bit 3-0 = Rate selection for periodic interrupt + 000 = periodic timer disabled + 001 = 3.90625 uS + 010 = 7.8125 uS + 011 = .122070 mS + 100 = .244141 mS + ... + 1101 = 125 mS + 1110 = 250 mS + 1111 = 500 mS +0Bh byte Register B + bit 7 = Run (0) / Halt (1) + bit 6 = Periodic interrupt enable + bit 5 = Alarm interrupt enable + bit 4 = Update-ended interrupt enable + bit 3 = Square wave interrupt enable + bit 2 = BCD calendar (0) / Binary (1) + bit 1 = 12-hour mode (0) / 24-hour mode (1) + bit 0 = 0 (DST off) / 1 (DST enabled) +OCh byte Register C (read only) + bit 7 = interrupt request flag (IRQF) + bit 6 = periodic interrupt flag (PF) + bit 5 = alarm interrupt flag (AF) + bit 4 = update interrupt flag (UF) + bit 3-0 = reserved +ODh byte Register D (read only) + bit 7 = RTC has power + bit 6-0 = reserved +32h byte Current century BCD (*) + (*) location vendor specific and now determined from ACPI global tables + +2.3) APIC + +On Pentium and later processors, an on-board timer is available to each CPU +as part of the Advanced Programmable Interrupt Controller. The APIC is +accessed through memory-mapped registers and provides interrupt service to each +CPU, used for IPIs and local timer interrupts. + +Although in theory the APIC is a safe and stable source for local interrupts, +in practice, many bugs and glitches have occurred due to the special nature of +the APIC CPU-local memory-mapped hardware. Beware that CPU errata may affect +the use of the APIC and that workarounds may be required. In addition, some of +these workarounds pose unique constraints for virtualization - requiring either +extra overhead incurred from extra reads of memory-mapped I/O or additional +functionality that may be more computationally expensive to implement. + +Since the APIC is documented quite well in the Intel and AMD manuals, we will +avoid repetition of the detail here. It should be pointed out that the APIC +timer is programmed through the LVT (local vector timer) register, is capable +of one-shot or periodic operation, and is based on the bus clock divided down +by the programmable divider register. + +2.4) HPET + +HPET is quite complex, and was originally intended to replace the PIT / RTC +support of the X86 PC. It remains to be seen whether that will be the case, as +the de facto standard of PC hardware is to emulate these older devices. Some +systems designated as legacy free may support only the HPET as a hardware timer +device. + +The HPET spec is rather loose and vague, requiring at least 3 hardware timers, +but allowing implementation freedom to support many more. It also imposes no +fixed rate on the timer frequency, but does impose some extremal values on +frequency, error and slew. + +In general, the HPET is recommended as a high precision (compared to PIT /RTC) +time source which is independent of local variation (as there is only one HPET +in any given system). The HPET is also memory-mapped, and its presence is +indicated through ACPI tables by the BIOS. + +Detailed specification of the HPET is beyond the current scope of this +document, as it is also very well documented elsewhere. + +2.5) Offboard Timers + +Several cards, both proprietary (watchdog boards) and commonplace (e1000) have +timing chips built into the cards which may have registers which are accessible +to kernel or user drivers. To the author's knowledge, using these to generate +a clocksource for a Linux or other kernel has not yet been attempted and is in +general frowned upon as not playing by the agreed rules of the game. Such a +timer device would require additional support to be virtualized properly and is +not considered important at this time as no known operating system does this. + +========================================================================= + +3) TSC Hardware + +The TSC or time stamp counter is relatively simple in theory; it counts +instruction cycles issued by the processor, which can be used as a measure of +time. In practice, due to a number of problems, it is the most complicated +timekeeping device to use. + +The TSC is represented internally as a 64-bit MSR which can be read with the +RDMSR, RDTSC, or RDTSCP (when available) instructions. In the past, hardware +limitations made it possible to write the TSC, but generally on old hardware it +was only possible to write the low 32-bits of the 64-bit counter, and the upper +32-bits of the counter were cleared. Now, however, on Intel processors family +0Fh, for models 3, 4 and 6, and family 06h, models e and f, this restriction +has been lifted and all 64-bits are writable. On AMD systems, the ability to +write the TSC MSR is not an architectural guarantee. + +The TSC is accessible from CPL-0 and conditionally, for CPL > 0 software by +means of the CR4.TSD bit, which when enabled, disables CPL > 0 TSC access. + +Some vendors have implemented an additional instruction, RDTSCP, which returns +atomically not just the TSC, but an indicator which corresponds to the +processor number. This can be used to index into an array of TSC variables to +determine offset information in SMP systems where TSCs are not synchronized. +The presence of this instruction must be determined by consulting CPUID feature +bits. + +Both VMX and SVM provide extension fields in the virtualization hardware which +allows the guest visible TSC to be offset by a constant. Newer implementations +promise to allow the TSC to additionally be scaled, but this hardware is not +yet widely available. + +3.1) TSC synchronization + +The TSC is a CPU-local clock in most implementations. This means, on SMP +platforms, the TSCs of different CPUs may start at different times depending +on when the CPUs are powered on. Generally, CPUs on the same die will share +the same clock, however, this is not always the case. + +The BIOS may attempt to resynchronize the TSCs during the poweron process and +the operating system or other system software may attempt to do this as well. +Several hardware limitations make the problem worse - if it is not possible to +write the full 64-bits of the TSC, it may be impossible to match the TSC in +newly arriving CPUs to that of the rest of the system, resulting in +unsynchronized TSCs. This may be done by BIOS or system software, but in +practice, getting a perfectly synchronized TSC will not be possible unless all +values are read from the same clock, which generally only is possible on single +socket systems or those with special hardware support. + +3.2) TSC and CPU hotplug + +As touched on already, CPUs which arrive later than the boot time of the system +may not have a TSC value that is synchronized with the rest of the system. +Either system software, BIOS, or SMM code may actually try to establish the TSC +to a value matching the rest of the system, but a perfect match is usually not +a guarantee. This can have the effect of bringing a system from a state where +TSC is synchronized back to a state where TSC synchronization flaws, however +small, may be exposed to the OS and any virtualization environment. + +3.3) TSC and multi-socket / NUMA + +Multi-socket systems, especially large multi-socket systems are likely to have +individual clocksources rather than a single, universally distributed clock. +Since these clocks are driven by different crystals, they will not have +perfectly matched frequency, and temperature and electrical variations will +cause the CPU clocks, and thus the TSCs to drift over time. Depending on the +exact clock and bus design, the drift may or may not be fixed in absolute +error, and may accumulate over time. + +In addition, very large systems may deliberately slew the clocks of individual +cores. This technique, known as spread-spectrum clocking, reduces EMI at the +clock frequency and harmonics of it, which may be required to pass FCC +standards for telecommunications and computer equipment. + +It is recommended not to trust the TSCs to remain synchronized on NUMA or +multiple socket systems for these reasons. + +3.4) TSC and C-states + +C-states, or idling states of the processor, especially C1E and deeper sleep +states may be problematic for TSC as well. The TSC may stop advancing in such +a state, resulting in a TSC which is behind that of other CPUs when execution +is resumed. Such CPUs must be detected and flagged by the operating system +based on CPU and chipset identifications. + +The TSC in such a case may be corrected by catching it up to a known external +clocksource. + +3.5) TSC frequency change / P-states + +To make things slightly more interesting, some CPUs may change frequency. They +may or may not run the TSC at the same rate, and because the frequency change +may be staggered or slewed, at some points in time, the TSC rate may not be +known other than falling within a range of values. In this case, the TSC will +not be a stable time source, and must be calibrated against a known, stable, +external clock to be a usable source of time. + +Whether the TSC runs at a constant rate or scales with the P-state is model +dependent and must be determined by inspecting CPUID, chipset or vendor +specific MSR fields. + +In addition, some vendors have known bugs where the P-state is actually +compensated for properly during normal operation, but when the processor is +inactive, the P-state may be raised temporarily to service cache misses from +other processors. In such cases, the TSC on halted CPUs could advance faster +than that of non-halted processors. AMD Turion processors are known to have +this problem. + +3.6) TSC and STPCLK / T-states + +External signals given to the processor may also have the effect of stopping +the TSC. This is typically done for thermal emergency power control to prevent +an overheating condition, and typically, there is no way to detect that this +condition has happened. + +3.7) TSC virtualization - VMX + +VMX provides conditional trapping of RDTSC, RDMSR, WRMSR and RDTSCP +instructions, which is enough for full virtualization of TSC in any manner. In +addition, VMX allows passing through the host TSC plus an additional TSC_OFFSET +field specified in the VMCS. Special instructions must be used to read and +write the VMCS field. + +3.8) TSC virtualization - SVM + +SVM provides conditional trapping of RDTSC, RDMSR, WRMSR and RDTSCP +instructions, which is enough for full virtualization of TSC in any manner. In +addition, SVM allows passing through the host TSC plus an additional offset +field specified in the SVM control block. + +3.9) TSC feature bits in Linux + +In summary, there is no way to guarantee the TSC remains in perfect +synchronization unless it is explicitly guaranteed by the architecture. Even +if so, the TSCs in multi-sockets or NUMA systems may still run independently +despite being locally consistent. + +The following feature bits are used by Linux to signal various TSC attributes, +but they can only be taken to be meaningful for UP or single node systems. + +X86_FEATURE_TSC : The TSC is available in hardware +X86_FEATURE_RDTSCP : The RDTSCP instruction is available +X86_FEATURE_CONSTANT_TSC : The TSC rate is unchanged with P-states +X86_FEATURE_NONSTOP_TSC : The TSC does not stop in C-states +X86_FEATURE_TSC_RELIABLE : TSC sync checks are skipped (VMware) + +4) Virtualization Problems + +Timekeeping is especially problematic for virtualization because a number of +challenges arise. The most obvious problem is that time is now shared between +the host and, potentially, a number of virtual machines. Thus the virtual +operating system does not run with 100% usage of the CPU, despite the fact that +it may very well make that assumption. It may expect it to remain true to very +exacting bounds when interrupt sources are disabled, but in reality only its +virtual interrupt sources are disabled, and the machine may still be preempted +at any time. This causes problems as the passage of real time, the injection +of machine interrupts and the associated clock sources are no longer completely +synchronized with real time. + +This same problem can occur on native harware to a degree, as SMM mode may +steal cycles from the naturally on X86 systems when SMM mode is used by the +BIOS, but not in such an extreme fashion. However, the fact that SMM mode may +cause similar problems to virtualization makes it a good justification for +solving many of these problems on bare metal. + +4.1) Interrupt clocking + +One of the most immediate problems that occurs with legacy operating systems +is that the system timekeeping routines are often designed to keep track of +time by counting periodic interrupts. These interrupts may come from the PIT +or the RTC, but the problem is the same: the host virtualization engine may not +be able to deliver the proper number of interrupts per second, and so guest +time may fall behind. This is especially problematic if a high interrupt rate +is selected, such as 1000 HZ, which is unfortunately the default for many Linux +guests. + +There are three approaches to solving this problem; first, it may be possible +to simply ignore it. Guests which have a separate time source for tracking +'wall clock' or 'real time' may not need any adjustment of their interrupts to +maintain proper time. If this is not sufficient, it may be necessary to inject +additional interrupts into the guest in order to increase the effective +interrupt rate. This approach leads to complications in extreme conditions, +where host load or guest lag is too much to compensate for, and thus another +solution to the problem has risen: the guest may need to become aware of lost +ticks and compensate for them internally. Although promising in theory, the +implementation of this policy in Linux has been extremely error prone, and a +number of buggy variants of lost tick compensation are distributed across +commonly used Linux systems. + +Windows uses periodic RTC clocking as a means of keeping time internally, and +thus requires interrupt slewing to keep proper time. It does use a low enough +rate (ed: is it 18.2 Hz?) however that it has not yet been a problem in +practice. + +4.2) TSC sampling and serialization + +As the highest precision time source available, the cycle counter of the CPU +has aroused much interest from developers. As explained above, this timer has +many problems unique to its nature as a local, potentially unstable and +potentially unsynchronized source. One issue which is not unique to the TSC, +but is highlighted because of its very precise nature is sampling delay. By +definition, the counter, once read is already old. However, it is also +possible for the counter to be read ahead of the actual use of the result. +This is a consequence of the superscalar execution of the instruction stream, +which may execute instructions out of order. Such execution is called +non-serialized. Forcing serialized execution is necessary for precise +measurement with the TSC, and requires a serializing instruction, such as CPUID +or an MSR read. + +Since CPUID may actually be virtualized by a trap and emulate mechanism, this +serialization can pose a performance issue for hardware virtualization. An +accurate time stamp counter reading may therefore not always be available, and +it may be necessary for an implementation to guard against "backwards" reads of +the TSC as seen from other CPUs, even in an otherwise perfectly synchronized +system. + +4.3) Timespec aliasing + +Additionally, this lack of serialization from the TSC poses another challenge +when using results of the TSC when measured against another time source. As +the TSC is much higher precision, many possible values of the TSC may be read +while another clock is still expressing the same value. + +That is, you may read (T,T+10) while external clock C maintains the same value. +Due to non-serialized reads, you may actually end up with a range which +fluctuates - from (T-1.. T+10). Thus, any time calculated from a TSC, but +calibrated against an external value may have a range of valid values. +Re-calibrating this computation may actually cause time, as computed after the +calibration, to go backwards, compared with time computed before the +calibration. + +This problem is particularly pronounced with an internal time source in Linux, +the kernel time, which is expressed in the theoretically high resolution +timespec - but which advances in much larger granularity intervals, sometimes +at the rate of jiffies, and possibly in catchup modes, at a much larger step. + +This aliasing requires care in the computation and recalibration of kvmclock +and any other values derived from TSC computation (such as TSC virtualization +itself). + +4.4) Migration + +Migration of a virtual machine raises problems for timekeeping in two ways. +First, the migration itself may take time, during which interrupts cannot be +delivered, and after which, the guest time may need to be caught up. NTP may +be able to help to some degree here, as the clock correction required is +typically small enough to fall in the NTP-correctable window. + +An additional concern is that timers based off the TSC (or HPET, if the raw bus +clock is exposed) may now be running at different rates, requiring compensation +in some way in the hypervisor by virtualizing these timers. In addition, +migrating to a faster machine may preclude the use of a passthrough TSC, as a +faster clock cannot be made visible to a guest without the potential of time +advancing faster than usual. A slower clock is less of a problem, as it can +always be caught up to the original rate. KVM clock avoids these problems by +simply storing multipliers and offsets against the TSC for the guest to convert +back into nanosecond resolution values. + +4.5) Scheduling + +Since scheduling may be based on precise timing and firing of interrupts, the +scheduling algorithms of an operating system may be adversely affected by +virtualization. In theory, the effect is random and should be universally +distributed, but in contrived as well as real scenarios (guest device access, +causes of virtualization exits, possible context switch), this may not always +be the case. The effect of this has not been well studied. + +In an attempt to work around this, several implementations have provided a +paravirtualized scheduler clock, which reveals the true amount of CPU time for +which a virtual machine has been running. + +4.6) Watchdogs + +Watchdog timers, such as the lock detector in Linux may fire accidentally when +running under hardware virtualization due to timer interrupts being delayed or +misinterpretation of the passage of real time. Usually, these warnings are +spurious and can be ignored, but in some circumstances it may be necessary to +disable such detection. + +4.7) Delays and precision timing + +Precise timing and delays may not be possible in a virtualized system. This +can happen if the system is controlling physical hardware, or issues delays to +compensate for slower I/O to and from devices. The first issue is not solvable +in general for a virtualized system; hardware control software can't be +adequately virtualized without a full real-time operating system, which would +require an RT aware virtualization platform. + +The second issue may cause performance problems, but this is unlikely to be a +significant issue. In many cases these delays may be eliminated through +configuration or paravirtualization. + +4.8) Covert channels and leaks + +In addition to the above problems, time information will inevitably leak to the +guest about the host in anything but a perfect implementation of virtualized +time. This may allow the guest to infer the presence of a hypervisor (as in a +red-pill type detection), and it may allow information to leak between guests +by using CPU utilization itself as a signalling channel. Preventing such +problems would require completely isolated virtual time which may not track +real time any longer. This may be useful in certain security or QA contexts, +but in general isn't recommended for real-world deployment scenarios. diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 8a6a8c6d4980..dc73bc54cc4e 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -1640,15 +1640,6 @@ static void blk_request(struct virtqueue *vq) off = out->sector * 512; /* - * The block device implements "barriers", where the Guest indicates - * that it wants all previous writes to occur before this write. We - * don't have a way of asking our kernel to do a barrier, so we just - * synchronize all the data in the file. Pretty poor, no? - */ - if (out->type & VIRTIO_BLK_T_BARRIER) - fdatasync(vblk->fd); - - /* * In general the virtio block driver is allowed to try SCSI commands. * It'd be nice if we supported eject, for example, but we don't. */ @@ -1680,6 +1671,13 @@ static void blk_request(struct virtqueue *vq) /* Die, bad Guest, die. */ errx(1, "Write past end %llu+%u", off, ret); } + + wlen = sizeof(*in); + *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); + } else if (out->type & VIRTIO_BLK_T_FLUSH) { + /* Flush */ + ret = fdatasync(vblk->fd); + verbose("FLUSH fdatasync: %i\n", ret); wlen = sizeof(*in); *in = (ret >= 0 ? VIRTIO_BLK_S_OK : VIRTIO_BLK_S_IOERR); } else { @@ -1703,15 +1701,6 @@ static void blk_request(struct virtqueue *vq) } } - /* - * OK, so we noted that it was pretty poor to use an fdatasync as a - * barrier. But Christoph Hellwig points out that we need a sync - * *afterwards* as well: "Barriers specify no reordering to the front - * or the back." And Jens Axboe confirmed it, so here we are: - */ - if (out->type & VIRTIO_BLK_T_BARRIER) - fdatasync(vblk->fd); - /* Finished that request. */ add_used(vq, head, wlen); } @@ -1736,8 +1725,8 @@ static void setup_block_file(const char *filename) vblk->fd = open_or_die(filename, O_RDWR|O_LARGEFILE); vblk->len = lseek64(vblk->fd, 0, SEEK_END); - /* We support barriers. */ - add_feature(dev, VIRTIO_BLK_F_BARRIER); + /* We support FLUSH. */ + add_feature(dev, VIRTIO_BLK_F_FLUSH); /* Tell Guest how many sectors this device has. */ conf.capacity = cpu_to_le64(vblk->len / 512); diff --git a/Documentation/networking/bonding.txt b/Documentation/networking/bonding.txt index d2b62b71b617..5dc638791d97 100644 --- a/Documentation/networking/bonding.txt +++ b/Documentation/networking/bonding.txt @@ -765,6 +765,14 @@ xmit_hash_policy does not exist, and the layer2 policy is the only policy. The layer2+3 value was added for bonding version 3.2.2. +resend_igmp + + Specifies the number of IGMP membership reports to be issued after + a failover event. One membership report is issued immediately after + the failover, subsequent packets are sent in each 200ms interval. + + The valid range is 0 - 255; the default value is 1. This option + was added for bonding version 3.7.0. 3. Configuring Bonding Devices ============================== diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt index cd79735013f9..5b04b67ddca2 100644 --- a/Documentation/networking/can.txt +++ b/Documentation/networking/can.txt @@ -22,6 +22,7 @@ This file contains 4.1.2 RAW socket option CAN_RAW_ERR_FILTER 4.1.3 RAW socket option CAN_RAW_LOOPBACK 4.1.4 RAW socket option CAN_RAW_RECV_OWN_MSGS + 4.1.5 RAW socket returned message flags 4.2 Broadcast Manager protocol sockets (SOCK_DGRAM) 4.3 connected transport protocols (SOCK_SEQPACKET) 4.4 unconnected transport protocols (SOCK_DGRAM) @@ -471,6 +472,17 @@ solution for a couple of reasons: setsockopt(s, SOL_CAN_RAW, CAN_RAW_RECV_OWN_MSGS, &recv_own_msgs, sizeof(recv_own_msgs)); + 4.1.5 RAW socket returned message flags + + When using recvmsg() call, the msg->msg_flags may contain following flags: + + MSG_DONTROUTE: set when the received frame was created on the local host. + + MSG_CONFIRM: set when the frame was sent via the socket it is received on. + This flag can be interpreted as a 'transmission confirmation' when the + CAN driver supports the echo of frames on driver level, see 3.2 and 6.2. + In order to receive such messages, CAN_RAW_RECV_OWN_MSGS must be set. + 4.2 Broadcast Manager protocol sockets (SOCK_DGRAM) 4.3 connected transport protocols (SOCK_SEQPACKET) 4.4 unconnected transport protocols (SOCK_DGRAM) diff --git a/Documentation/networking/dccp.txt b/Documentation/networking/dccp.txt index a62fdf7a6bff..271d524a4c8d 100644 --- a/Documentation/networking/dccp.txt +++ b/Documentation/networking/dccp.txt @@ -1,18 +1,20 @@ DCCP protocol -============ +============= Contents ======== - - Introduction - Missing features - Socket options +- Sysctl variables +- IOCTLs +- Other tunables - Notes + Introduction ============ - Datagram Congestion Control Protocol (DCCP) is an unreliable, connection oriented protocol designed to solve issues present in UDP and TCP, particularly for real-time and multimedia (streaming) traffic. @@ -29,9 +31,9 @@ It has a base protocol and pluggable congestion control IDs (CCIDs). DCCP is a Proposed Standard (RFC 2026), and the homepage for DCCP as a protocol is at http://www.ietf.org/html.charters/dccp-charter.html + Missing features ================ - The Linux DCCP implementation does not currently support all the features that are specified in RFCs 4340...42. @@ -45,7 +47,6 @@ http://linux-net.osdl.org/index.php/DCCP_Testing#Experimental_DCCP_source_tree Socket options ============== - DCCP_SOCKOPT_SERVICE sets the service. The specification mandates use of service codes (RFC 4340, sec. 8.1.2); if this socket option is not set, the socket will fall back to 0 (which means that no meaningful service code @@ -112,6 +113,7 @@ DCCP_SOCKOPT_CCID_TX_INFO On unidirectional connections it is useful to close the unused half-connection via shutdown (SHUT_WR or SHUT_RD): this will reduce per-packet processing costs. + Sysctl variables ================ Several DCCP default parameters can be managed by the following sysctls @@ -155,15 +157,30 @@ sync_ratelimit = 125 ms sequence-invalid packets on the same socket (RFC 4340, 7.5.4). The unit of this parameter is milliseconds; a value of 0 disables rate-limiting. + IOCTLS ====== FIONREAD Works as in udp(7): returns in the `int' argument pointer the size of the next pending datagram in bytes, or 0 when no datagram is pending. + +Other tunables +============== +Per-route rto_min support + CCID-2 supports the RTAX_RTO_MIN per-route setting for the minimum value + of the RTO timer. This setting can be modified via the 'rto_min' option + of iproute2; for example: + > ip route change 10.0.0.0/24 rto_min 250j dev wlan0 + > ip route add 10.0.0.254/32 rto_min 800j dev wlan0 + > ip route show dev wlan0 + CCID-3 also supports the rto_min setting: it is used to define the lower + bound for the expiry of the nofeedback timer. This can be useful on LANs + with very low RTTs (e.g., loopback, Gbit ethernet). + + Notes ===== - DCCP does not travel through NAT successfully at present on many boxes. This is because the checksum covers the pseudo-header as per TCP and UDP. Linux NAT support for DCCP has been added. diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index f350c69b2bb4..c7165f4cb792 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -1014,6 +1014,12 @@ conf/interface/*: accept_ra - BOOLEAN Accept Router Advertisements; autoconfigure using them. + Possible values are: + 0 Do not accept Router Advertisements. + 1 Accept Router Advertisements if forwarding is disabled. + 2 Overrule forwarding behaviour. Accept Router Advertisements + even if forwarding is enabled. + Functional default: enabled if local forwarding is disabled. disabled if local forwarding is enabled. @@ -1075,7 +1081,12 @@ forwarding - BOOLEAN Note: It is recommended to have the same setting on all interfaces; mixed router/host scenarios are rather uncommon. - FALSE: + Possible values are: + 0 Forwarding disabled + 1 Forwarding enabled + 2 Forwarding enabled (Hybrid Mode) + + FALSE (0): By default, Host behaviour is assumed. This means: @@ -1085,18 +1096,24 @@ forwarding - BOOLEAN Advertisements (and do autoconfiguration). 4. If accept_redirects is TRUE (default), accept Redirects. - TRUE: + TRUE (1): If local forwarding is enabled, Router behaviour is assumed. This means exactly the reverse from the above: 1. IsRouter flag is set in Neighbour Advertisements. 2. Router Solicitations are not sent. - 3. Router Advertisements are ignored. + 3. Router Advertisements are ignored unless accept_ra is 2. 4. Redirects are ignored. - Default: FALSE if global forwarding is disabled (default), - otherwise TRUE. + TRUE (2): + + Hybrid mode. Same behaviour as TRUE, except for: + + 2. Router Solicitations are being sent when necessary. + + Default: 0 (disabled) if global forwarding is disabled (default), + otherwise 1 (enabled). hop_limit - INTEGER Default Hop Limit to set. diff --git a/Documentation/networking/phonet.txt b/Documentation/networking/phonet.txt index 6e8ce09f9c73..24ad2adba6e5 100644 --- a/Documentation/networking/phonet.txt +++ b/Documentation/networking/phonet.txt @@ -112,6 +112,22 @@ However, connect() and getpeername() are not supported, as they did not seem useful with Phonet usages (could be added easily). +Resource subscription +--------------------- + +A Phonet datagram socket can be subscribed to any number of 8-bits +Phonet resources, as follow: + + uint32_t res = 0xXX; + ioctl(fd, SIOCPNADDRESOURCE, &res); + +Subscription is similarly cancelled using the SIOCPNDELRESOURCE I/O +control request, or when the socket is closed. + +Note that no more than one socket can be subcribed to any given +resource at a time. If not, ioctl() will return EBUSY. + + Phonet Pipe protocol -------------------- @@ -166,6 +182,46 @@ The pipe protocol provides two socket options at the SOL_PNPIPE level: or zero if encapsulation is off. +Phonet Pipe-controller Implementation +------------------------------------- + +Phonet Pipe-controller is enabled by selecting the CONFIG_PHONET_PIPECTRLR Kconfig +option. It is useful when communicating with those Nokia Modems which do not +implement Pipe controller in them e.g. Nokia Slim Modem used in ST-Ericsson +U8500 platform. + +The implementation is based on the Data Connection Establishment Sequence +depicted in 'Nokia Wireless Modem API - Wireless_modem_user_guide.pdf' +document. + +It allows a phonet sequenced socket (host-pep) to initiate a Pipe connection +between itself and a remote pipe-end point (e.g. modem). + +The implementation adds socket options at SOL_PNPIPE level: + + PNPIPE_PIPE_HANDLE + It accepts an integer argument for setting value of pipe handle. + + PNPIPE_ENABLE accepts one integer value (int). If set to zero, the pipe + is disabled. If the value is non-zero, the pipe is enabled. If the pipe + is not (yet) connected, ENOTCONN is error is returned. + +The implementation also adds socket 'connect'. On calling the 'connect', pipe +will be created between the source socket and the destination, and the pipe +state will be set to PIPE_DISABLED. + +After a pipe has been created and enabled successfully, the Pipe data can be +exchanged between the host-pep and remote-pep (modem). + +User-space would typically follow below sequence with Pipe controller:- +-socket +-bind +-setsockopt for PNPIPE_PIPE_HANDLE +-connect +-setsockopt for PNPIPE_ENCAP_IP +-setsockopt for PNPIPE_ENABLE + + Authors ------- diff --git a/Documentation/networking/timestamping.txt b/Documentation/networking/timestamping.txt index e8c8f4f06c67..98097d8cb910 100644 --- a/Documentation/networking/timestamping.txt +++ b/Documentation/networking/timestamping.txt @@ -172,15 +172,19 @@ struct skb_shared_hwtstamps { }; Time stamps for outgoing packets are to be generated as follows: -- In hard_start_xmit(), check if skb_tx(skb)->hardware is set no-zero. - If yes, then the driver is expected to do hardware time stamping. +- In hard_start_xmit(), check if (skb_shinfo(skb)->tx_flags & SKBTX_HW_TSTAMP) + is set no-zero. If yes, then the driver is expected to do hardware time + stamping. - If this is possible for the skb and requested, then declare - that the driver is doing the time stamping by setting the field - skb_tx(skb)->in_progress non-zero. You might want to keep a pointer - to the associated skb for the next step and not free the skb. A driver - not supporting hardware time stamping doesn't do that. A driver must - never touch sk_buff::tstamp! It is used to store software generated - time stamps by the network subsystem. + that the driver is doing the time stamping by setting the flag + SKBTX_IN_PROGRESS in skb_shinfo(skb)->tx_flags , e.g. with + + skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS; + + You might want to keep a pointer to the associated skb for the next step + and not free the skb. A driver not supporting hardware time stamping doesn't + do that. A driver must never touch sk_buff::tstamp! It is used to store + software generated time stamps by the network subsystem. - As soon as the driver has sent the packet and/or obtained a hardware time stamp for it, it passes the time stamp back by calling skb_hwtstamp_tx() with the original skb, the raw @@ -191,6 +195,6 @@ Time stamps for outgoing packets are to be generated as follows: this would occur at a later time in the processing pipeline than other software time stamping and therefore could lead to unexpected deltas between time stamps. -- If the driver did not call set skb_tx(skb)->in_progress, then +- If the driver did not set the SKBTX_IN_PROGRESS flag (see above), then dev_hard_start_xmit() checks whether software time stamping is wanted as fallback and potentially generates the time stamp. diff --git a/Documentation/powerpc/dts-bindings/fsl/usb.txt b/Documentation/powerpc/dts-bindings/fsl/usb.txt index b00152402694..bd5723f0b67e 100644 --- a/Documentation/powerpc/dts-bindings/fsl/usb.txt +++ b/Documentation/powerpc/dts-bindings/fsl/usb.txt @@ -8,6 +8,7 @@ and additions : Required properties : - compatible : Should be "fsl-usb2-mph" for multi port host USB controllers, or "fsl-usb2-dr" for dual role USB controllers + or "fsl,mpc5121-usb2-dr" for dual role USB controllers of MPC5121 - phy_type : For multi port host USB controllers, should be one of "ulpi", or "serial". For dual role USB controllers, should be one of "ulpi", "utmi", "utmi_wide", or "serial". @@ -33,6 +34,12 @@ Recommended properties : - interrupt-parent : the phandle for the interrupt controller that services interrupts for this device. +Optional properties : + - fsl,invert-drvvbus : boolean; for MPC5121 USB0 only. Indicates the + port power polarity of internal PHY signal DRVVBUS is inverted. + - fsl,invert-pwr-fault : boolean; for MPC5121 USB0 only. Indicates + the PWR_FAULT signal polarity is inverted. + Example multi port host USB controller device node : usb@22000 { compatible = "fsl-usb2-mph"; @@ -57,3 +64,18 @@ Example dual role USB controller device node : dr_mode = "otg"; phy = "ulpi"; }; + +Example dual role USB controller device node for MPC5121ADS: + + usb@4000 { + compatible = "fsl,mpc5121-usb2-dr"; + reg = <0x4000 0x1000>; + #address-cells = <1>; + #size-cells = <0>; + interrupt-parent = < &ipic >; + interrupts = <44 0x8>; + dr_mode = "otg"; + phy_type = "utmi_wide"; + fsl,invert-drvvbus; + fsl,invert-pwr-fault; + }; diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt index 40752602c050..691ca292c24d 100644 --- a/Documentation/scsi/st.txt +++ b/Documentation/scsi/st.txt @@ -2,7 +2,7 @@ This file contains brief information about the SCSI tape driver. The driver is currently maintained by Kai Mäkisara (email Kai.Makisara@kolumbus.fi) -Last modified: Sun Feb 24 21:59:07 2008 by kai.makisara +Last modified: Sun Aug 29 18:25:47 2010 by kai.makisara BASICS @@ -85,6 +85,17 @@ writing and the last operation has been a write. Two filemarks can be optionally written. In both cases end of data is signified by returning zero bytes for two consecutive reads. +Writing filemarks without the immediate bit set in the SCSI command block acts +as a synchronization point, i.e., all remaining data form the drive buffers is +written to tape before the command returns. This makes sure that write errors +are caught at that point, but this takes time. In some applications, several +consecutive files must be written fast. The MTWEOFI operation can be used to +write the filemarks without flushing the drive buffer. Writing filemark at +close() is always flushing the drive buffers. However, if the previous +operation is MTWEOFI, close() does not write a filemark. This can be used if +the program wants to close/open the tape device between files and wants to +skip waiting. + If rewind, offline, bsf, or seek is done and previous tape operation was write, a filemark is written before moving tape. @@ -301,6 +312,8 @@ MTBSR Space backward over count records. MTFSS Space forward over count setmarks. MTBSS Space backward over count setmarks. MTWEOF Write count filemarks. +MTWEOFI Write count filemarks with immediate bit set (i.e., does not + wait until data is on tape) MTWSM Write count setmarks. MTREW Rewind tape. MTOFFL Set device off line (often rewind plus eject). diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt index 7f4dcebda9c6..d0eb696d32e8 100644 --- a/Documentation/sound/alsa/ALSA-Configuration.txt +++ b/Documentation/sound/alsa/ALSA-Configuration.txt @@ -300,6 +300,74 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. control correctly. If you have problems regarding this, try another ALSA compliant mixer (alsamixer works). + Module snd-azt1605 + ------------------ + + Module for Aztech Sound Galaxy soundcards based on the Aztech AZT1605 + chipset. + + port - port # for BASE (0x220,0x240,0x260,0x280) + wss_port - port # for WSS (0x530,0x604,0xe80,0xf40) + irq - IRQ # for WSS (7,9,10,11) + dma1 - DMA # for WSS playback (0,1,3) + dma2 - DMA # for WSS capture (0,1), -1 = disabled (default) + mpu_port - port # for MPU-401 UART (0x300,0x330), -1 = disabled (default) + mpu_irq - IRQ # for MPU-401 UART (3,5,7,9), -1 = disabled (default) + fm_port - port # for OPL3 (0x388), -1 = disabled (default) + + This module supports multiple cards. It does not support autoprobe: port, + wss_port, irq and dma1 have to be specified. The other values are + optional. + + "port" needs to match the BASE ADDRESS jumper on the card (0x220 or 0x240) + or the value stored in the card's EEPROM for cards that have an EEPROM and + their "CONFIG MODE" jumper set to "EEPROM SETTING". The other values can + be choosen freely from the options enumerated above. + + If dma2 is specified and different from dma1, the card will operate in + full-duplex mode. When dma1=3, only dma2=0 is valid and the only way to + enable capture since only channels 0 and 1 are available for capture. + + Generic settings are "port=0x220 wss_port=0x530 irq=10 dma1=1 dma2=0 + mpu_port=0x330 mpu_irq=9 fm_port=0x388". + + Whatever IRQ and DMA channels you pick, be sure to reserve them for + legacy ISA in your BIOS. + + Module snd-azt2316 + ------------------ + + Module for Aztech Sound Galaxy soundcards based on the Aztech AZT2316 + chipset. + + port - port # for BASE (0x220,0x240,0x260,0x280) + wss_port - port # for WSS (0x530,0x604,0xe80,0xf40) + irq - IRQ # for WSS (7,9,10,11) + dma1 - DMA # for WSS playback (0,1,3) + dma2 - DMA # for WSS capture (0,1), -1 = disabled (default) + mpu_port - port # for MPU-401 UART (0x300,0x330), -1 = disabled (default) + mpu_irq - IRQ # for MPU-401 UART (5,7,9,10), -1 = disabled (default) + fm_port - port # for OPL3 (0x388), -1 = disabled (default) + + This module supports multiple cards. It does not support autoprobe: port, + wss_port, irq and dma1 have to be specified. The other values are + optional. + + "port" needs to match the BASE ADDRESS jumper on the card (0x220 or 0x240) + or the value stored in the card's EEPROM for cards that have an EEPROM and + their "CONFIG MODE" jumper set to "EEPROM SETTING". The other values can + be choosen freely from the options enumerated above. + + If dma2 is specified and different from dma1, the card will operate in + full-duplex mode. When dma1=3, only dma2=0 is valid and the only way to + enable capture since only channels 0 and 1 are available for capture. + + Generic settings are "port=0x220 wss_port=0x530 irq=10 dma1=1 dma2=0 + mpu_port=0x330 mpu_irq=9 fm_port=0x388". + + Whatever IRQ and DMA channels you pick, be sure to reserve them for + legacy ISA in your BIOS. + Module snd-aw2 -------------- @@ -1641,20 +1709,6 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed. This card is also known as Audio Excel DSP 16 or Zoltrix AV302. - Module snd-sgalaxy - ------------------ - - Module for Aztech Sound Galaxy sound card. - - sbport - Port # for SB16 interface (0x220,0x240) - wssport - Port # for WSS interface (0x530,0xe80,0xf40,0x604) - irq - IRQ # (7,9,10,11) - dma1 - DMA # - - This module supports multiple cards. - - The power-management is supported. - Module snd-sscape ----------------- diff --git a/Documentation/sound/alsa/HD-Audio.txt b/Documentation/sound/alsa/HD-Audio.txt index 278cc2122ea0..c82beb007634 100644 --- a/Documentation/sound/alsa/HD-Audio.txt +++ b/Documentation/sound/alsa/HD-Audio.txt @@ -57,9 +57,11 @@ dead. However, this detection isn't perfect on some devices. In such a case, you can change the default method via `position_fix` option. `position_fix=1` means to use LPIB method explicitly. -`position_fix=2` means to use the position-buffer. 0 is the default -value, the automatic check and fallback to LPIB as described in the -above. If you get a problem of repeated sounds, this option might +`position_fix=2` means to use the position-buffer. +`position_fix=3` means to use a combination of both methods, needed +for some VIA and ATI controllers. 0 is the default value for all other +controllers, the automatic check and fallback to LPIB as described in +the above. If you get a problem of repeated sounds, this option might help. In addition to that, every controller is known to be broken regarding diff --git a/Documentation/usb/proc_usb_info.txt b/Documentation/usb/proc_usb_info.txt index fafcd4723260..afe596d5f201 100644 --- a/Documentation/usb/proc_usb_info.txt +++ b/Documentation/usb/proc_usb_info.txt @@ -1,12 +1,17 @@ /proc/bus/usb filesystem output =============================== -(version 2003.05.30) +(version 2010.09.13) The usbfs filesystem for USB devices is traditionally mounted at /proc/bus/usb. It provides the /proc/bus/usb/devices file, as well as the /proc/bus/usb/BBB/DDD files. +In many modern systems the usbfs filsystem isn't used at all. Instead +USB device nodes are created under /dev/usb/ or someplace similar. The +"devices" file is available in debugfs, typically as +/sys/kernel/debug/usb/devices. + **NOTE**: If /proc/bus/usb appears empty, and a host controller driver has been linked, then you need to mount the @@ -106,8 +111,8 @@ Legend: Topology info: -T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=ddd MxCh=dd -| | | | | | | | |__MaxChildren +T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=dddd MxCh=dd +| | | | | | | | |__MaxChildren | | | | | | | |__Device Speed in Mbps | | | | | | |__DeviceNumber | | | | | |__Count of devices at this level @@ -120,8 +125,13 @@ T: Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=ddd MxCh=dd Speed may be: 1.5 Mbit/s for low speed USB 12 Mbit/s for full speed USB - 480 Mbit/s for high speed USB (added for USB 2.0) + 480 Mbit/s for high speed USB (added for USB 2.0); + also used for Wireless USB, which has no fixed speed + 5000 Mbit/s for SuperSpeed USB (added for USB 3.0) + For reasons lost in the mists of time, the Port number is always + too low by 1. For example, a device plugged into port 4 will + show up with "Port=03". Bandwidth info: B: Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd @@ -291,7 +301,7 @@ Here's an example, from a system which has a UHCI root hub, an external hub connected to the root hub, and a mouse and a serial converter connected to the external hub. -T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 +T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 B: Alloc= 28/900 us ( 3%), #Int= 2, #Iso= 0 D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=0000 ProdID=0000 Rev= 0.00 @@ -301,21 +311,21 @@ C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr= 0mA I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub E: Ad=81(I) Atr=03(Int.) MxPS= 8 Ivl=255ms -T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4 +T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4 D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=0451 ProdID=1446 Rev= 1.00 C:* #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=100mA I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub E: Ad=81(I) Atr=03(Int.) MxPS= 1 Ivl=255ms -T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0 +T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0 D: Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=04b4 ProdID=0001 Rev= 0.00 C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=100mA I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=01 Prot=02 Driver=mouse E: Ad=81(I) Atr=03(Int.) MxPS= 3 Ivl= 10ms -T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0 +T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0 D: Ver= 1.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=0565 ProdID=0001 Rev= 1.08 S: Manufacturer=Peracom Networks, Inc. @@ -330,12 +340,12 @@ E: Ad=82(I) Atr=03(Int.) MxPS= 8 Ivl= 8ms Selecting only the "T:" and "I:" lines from this (for example, by using "procusb ti"), we have: -T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 -T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4 +T: Bus=00 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 +T: Bus=00 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh= 4 I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub -T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0 +T: Bus=00 Lev=02 Prnt=02 Port=00 Cnt=01 Dev#= 3 Spd=1.5 MxCh= 0 I: If#= 0 Alt= 0 #EPs= 1 Cls=03(HID ) Sub=01 Prot=02 Driver=mouse -T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0 +T: Bus=00 Lev=02 Prnt=02 Port=02 Cnt=02 Dev#= 4 Spd=12 MxCh= 0 I: If#= 0 Alt= 0 #EPs= 3 Cls=00(>ifc ) Sub=00 Prot=00 Driver=serial diff --git a/Documentation/vm/numa_memory_policy.txt b/Documentation/vm/numa_memory_policy.txt index 6690fc34ef6d..4e7da6543424 100644 --- a/Documentation/vm/numa_memory_policy.txt +++ b/Documentation/vm/numa_memory_policy.txt @@ -424,7 +424,7 @@ a command line tool, numactl(8), exists that allows one to: + set the shared policy for a shared memory segment via mbind(2) -The numactl(8) tool is packages with the run-time version of the library +The numactl(8) tool is packaged with the run-time version of the library containing the memory policy system call wrappers. Some distributions package the headers and compile-time libraries in a separate development package. diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt index e4498a2872c3..996a27d9b8db 100644 --- a/Documentation/workqueue.txt +++ b/Documentation/workqueue.txt @@ -196,11 +196,11 @@ resources, scheduled and executed. suspend operations. Work items on the wq are drained and no new work item starts execution until thawed. - WQ_RESCUER + WQ_MEM_RECLAIM All wq which might be used in the memory reclaim paths _MUST_ - have this flag set. This reserves one worker exclusively for - the execution of this wq under memory pressure. + have this flag set. The wq is guaranteed to have at least one + execution context regardless of memory pressure. WQ_HIGHPRI @@ -356,11 +356,11 @@ If q1 has WQ_CPU_INTENSIVE set, 6. Guidelines -* Do not forget to use WQ_RESCUER if a wq may process work items which - are used during memory reclaim. Each wq with WQ_RESCUER set has one - rescuer thread reserved for it. If there is dependency among - multiple work items used during memory reclaim, they should be - queued to separate wq each with WQ_RESCUER. +* Do not forget to use WQ_MEM_RECLAIM if a wq may process work items + which are used during memory reclaim. Each wq with WQ_MEM_RECLAIM + set has an execution context reserved for it. If there is + dependency among multiple work items used during memory reclaim, + they should be queued to separate wq each with WQ_MEM_RECLAIM. * Unless strict ordering is required, there is no need to use ST wq. @@ -368,12 +368,13 @@ If q1 has WQ_CPU_INTENSIVE set, recommended. In most use cases, concurrency level usually stays well under the default limit. -* A wq serves as a domain for forward progress guarantee (WQ_RESCUER), - flush and work item attributes. Work items which are not involved - in memory reclaim and don't need to be flushed as a part of a group - of work items, and don't require any special attribute, can use one - of the system wq. There is no difference in execution - characteristics between using a dedicated wq and a system wq. +* A wq serves as a domain for forward progress guarantee + (WQ_MEM_RECLAIM, flush and work item attributes. Work items which + are not involved in memory reclaim and don't need to be flushed as a + part of a group of work items, and don't require any special + attribute, can use one of the system wq. There is no difference in + execution characteristics between using a dedicated wq and a system + wq. * Unless work items are expected to consume a huge amount of CPU cycles, using a bound wq is usually beneficial due to the increased diff --git a/Documentation/x86/x86_64/kernel-stacks b/Documentation/x86/x86_64/kernel-stacks index 5ad65d51fb95..a01eec5d1d0b 100644 --- a/Documentation/x86/x86_64/kernel-stacks +++ b/Documentation/x86/x86_64/kernel-stacks @@ -18,9 +18,9 @@ specialized stacks contain no useful data. The main CPU stacks are: Used for external hardware interrupts. If this is the first external hardware interrupt (i.e. not a nested hardware interrupt) then the kernel switches from the current task to the interrupt stack. Like - the split thread and interrupt stacks on i386 (with CONFIG_4KSTACKS), - this gives more room for kernel interrupt processing without having - to increase the size of every per thread stack. + the split thread and interrupt stacks on i386, this gives more room + for kernel interrupt processing without having to increase the size + of every per thread stack. The interrupt stack is also used when processing a softirq. |