diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-05 07:11:28 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-08-05 07:11:28 +0400 |
commit | ae9b475ebed96afe51d6bcf10dc7aee9c8d89ed7 (patch) | |
tree | 374bf5821a03d717b35f0b91dcbdeaa2428e649d /Documentation | |
parent | 79eb238c76782a59d51adf8a3dd7f6444245b475 (diff) | |
parent | d310d05f1225d1f6f2bf505255fdf593bfbb3051 (diff) | |
download | linux-ae9b475ebed96afe51d6bcf10dc7aee9c8d89ed7.tar.xz |
Merge tag 'usb-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Pull USB updates from Greg KH:
"Here is the big USB driver update for 3.17-rc1.
Loads of gadget driver changes in here, including some big file
movements to make things easier to manage over time. There's also the
usual xhci and uas driver updates, and a handful of other changes in
here. The changelog has the full details.
All of these have been in linux-next for a while"
* tag 'usb-3.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (211 commits)
USB: devio: fix issue with log flooding
uas: Log a warning when we cannot use uas because the hcd lacks streams
uas: Only complain about missing sg if all other checks succeed
xhci: Add missing checks for xhci_alloc_command failure
xhci: Rename Asrock P67 pci product-id to EJ168
xhci: Blacklist using streams on the Etron EJ168 controller
uas: Limit qdepth to 32 when connected over usb-2
uwb/whci: use correct structure type name in sizeof
usb-core bInterval quirk
USB: serial: ftdi_sio: Add support for new Xsens devices
USB: serial: ftdi_sio: Annotate the current Xsens PID assignments
usb: chipidea: debug: fix sparse non static symbol warnings
usb: ci_hdrc_imx doc: fsl,usbphy is required
usb: ci_hdrc_imx: Return -EINVAL for missing USB PHY
usb: core: allow zero packet flag for interrupt urbs
usb: lvstest: Fix sparse warnings generated by kbuild test bot
USB: core: hcd-pci: free IRQ before disabling PCI device when shutting down
phy: miphy365x: Represent each PHY channel as a DT subnode
phy: miphy365x: Provide support for the MiPHY356x Generic PHY
phy: miphy365x: Add Device Tree bindings for the MiPHY365x
...
Diffstat (limited to 'Documentation')
17 files changed, 524 insertions, 31 deletions
diff --git a/Documentation/ABI/stable/sysfs-bus-usb b/Documentation/ABI/stable/sysfs-bus-usb index a6b685724740..e2bc700a6f9c 100644 --- a/Documentation/ABI/stable/sysfs-bus-usb +++ b/Documentation/ABI/stable/sysfs-bus-usb @@ -3,13 +3,13 @@ Date: May 2007 KernelVersion: 2.6.23 Contact: Alan Stern <stern@rowland.harvard.edu> Description: - If CONFIG_USB_PERSIST is set, then each USB device directory - will contain a file named power/persist. The file holds a - boolean value (0 or 1) indicating whether or not the - "USB-Persist" facility is enabled for the device. Since the - facility is inherently dangerous, it is disabled by default - for all devices except hubs. For more information, see - Documentation/usb/persist.txt. + USB device directories can contain a file named power/persist. + The file holds a boolean value (0 or 1) indicating whether or + not the "USB-Persist" facility is enabled for the device. For + hubs this facility is always enabled and their device + directories will not contain this file. + + For more information, see Documentation/usb/persist.txt. What: /sys/bus/usb/devices/.../power/autosuspend Date: March 2007 diff --git a/Documentation/ABI/testing/sysfs-bus-usb-lvstest b/Documentation/ABI/testing/sysfs-bus-usb-lvstest new file mode 100644 index 000000000000..aae68fc2d842 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-usb-lvstest @@ -0,0 +1,47 @@ +Link Layer Validation Device is a standard device for testing of Super +Speed Link Layer tests. These nodes are available in sysfs only when lvs +driver is bound with root hub device. + +What: /sys/bus/usb/devices/.../get_dev_desc +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Write to this node to issue "Get Device Descriptor" + for Link Layer Validation device. It is needed for TD.7.06. + +What: /sys/bus/usb/devices/.../u1_timeout +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Set "U1 timeout" for the downstream port where Link Layer + Validation device is connected. Timeout value must be between 0 + and 127. It is needed for TD.7.18, TD.7.19, TD.7.20 and TD.7.21. + +What: /sys/bus/usb/devices/.../u2_timeout +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Set "U2 timeout" for the downstream port where Link Layer + Validation device is connected. Timeout value must be between 0 + and 127. It is needed for TD.7.18, TD.7.19, TD.7.20 and TD.7.21. + +What: /sys/bus/usb/devices/.../hot_reset +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Write to this node to issue "Reset" for Link Layer Validation + device. It is needed for TD.7.29, TD.7.31, TD.7.34 and TD.7.35. + +What: /sys/bus/usb/devices/.../u3_entry +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Write to this node to issue "U3 entry" for Link Layer + Validation device. It is needed for TD.7.35 and TD.7.36. + +What: /sys/bus/usb/devices/.../u3_exit +Date: March 2014 +Contact: Pratyush Anand <pratyush.anand@st.com> +Description: + Write to this node to issue "U3 exit" for Link Layer + Validation device. It is needed for TD.7.36. diff --git a/Documentation/DocBook/gadget.tmpl b/Documentation/DocBook/gadget.tmpl index 2c425d70f7e2..641629221176 100644 --- a/Documentation/DocBook/gadget.tmpl +++ b/Documentation/DocBook/gadget.tmpl @@ -556,11 +556,11 @@ been converted to this framework. Near-term plans include converting all of them, except for "gadgetfs". </para> -!Edrivers/usb/gadget/f_acm.c -!Edrivers/usb/gadget/f_ecm.c -!Edrivers/usb/gadget/f_subset.c -!Edrivers/usb/gadget/f_obex.c -!Edrivers/usb/gadget/f_serial.c +!Edrivers/usb/gadget/function/f_acm.c +!Edrivers/usb/gadget/function/f_ecm.c +!Edrivers/usb/gadget/function/f_subset.c +!Edrivers/usb/gadget/function/f_obex.c +!Edrivers/usb/gadget/function/f_serial.c </sect1> diff --git a/Documentation/devicetree/bindings/phy/berlin-sata-phy.txt b/Documentation/devicetree/bindings/phy/berlin-sata-phy.txt new file mode 100644 index 000000000000..88f8c23384c0 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/berlin-sata-phy.txt @@ -0,0 +1,34 @@ +Berlin SATA PHY +--------------- + +Required properties: +- compatible: should be "marvell,berlin2q-sata-phy" +- address-cells: should be 1 +- size-cells: should be 0 +- phy-cells: from the generic PHY bindings, must be 1 +- reg: address and length of the register +- clocks: reference to the clock entry + +Sub-nodes: +Each PHY should be represented as a sub-node. + +Sub-nodes required properties: +- reg: the PHY number + +Example: + sata_phy: phy@f7e900a0 { + compatible = "marvell,berlin2q-sata-phy"; + reg = <0xf7e900a0 0x200>; + clocks = <&chip CLKID_SATA>; + #address-cells = <1>; + #size-cells = <0>; + #phy-cells = <1>; + + sata-phy@0 { + reg = <0>; + }; + + sata-phy@1 { + reg = <1>; + }; + }; diff --git a/Documentation/devicetree/bindings/phy/hix5hd2-phy.txt b/Documentation/devicetree/bindings/phy/hix5hd2-phy.txt new file mode 100644 index 000000000000..296168b74d24 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/hix5hd2-phy.txt @@ -0,0 +1,22 @@ +Hisilicon hix5hd2 SATA PHY +----------------------- + +Required properties: +- compatible: should be "hisilicon,hix5hd2-sata-phy" +- reg: offset and length of the PHY registers +- #phy-cells: must be 0 +Refer to phy/phy-bindings.txt for the generic PHY binding properties + +Optional Properties: +- hisilicon,peripheral-syscon: phandle of syscon used to control peripheral. +- hisilicon,power-reg: offset and bit number within peripheral-syscon, + register of controlling sata power supply. + +Example: + sata_phy: phy@f9900000 { + compatible = "hisilicon,hix5hd2-sata-phy"; + reg = <0xf9900000 0x10000>; + #phy-cells = <0>; + hisilicon,peripheral-syscon = <&peripheral_ctrl>; + hisilicon,power-reg = <0x8 10>; + }; diff --git a/Documentation/devicetree/bindings/phy/phy-bindings.txt b/Documentation/devicetree/bindings/phy/phy-bindings.txt index 8ae844fc0c60..2aa1840200ed 100644 --- a/Documentation/devicetree/bindings/phy/phy-bindings.txt +++ b/Documentation/devicetree/bindings/phy/phy-bindings.txt @@ -10,6 +10,10 @@ Required Properties: provider can use the values in cells to find the appropriate PHY. +Optional Properties: +phy-supply: Phandle to a regulator that provides power to the PHY. This + regulator will be managed during the PHY power on/off sequence. + For example: phys: phy { diff --git a/Documentation/devicetree/bindings/phy/phy-miphy365x.txt b/Documentation/devicetree/bindings/phy/phy-miphy365x.txt new file mode 100644 index 000000000000..42c880886cf7 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/phy-miphy365x.txt @@ -0,0 +1,76 @@ +STMicroelectronics STi MIPHY365x PHY binding +============================================ + +This binding describes a miphy device that is used to control PHY hardware +for SATA and PCIe. + +Required properties (controller (parent) node): +- compatible : Should be "st,miphy365x-phy" +- st,syscfg : Should be a phandle of the system configuration register group + which contain the SATA, PCIe mode setting bits + +Required nodes : A sub-node is required for each channel the controller + provides. Address range information including the usual + 'reg' and 'reg-names' properties are used inside these + nodes to describe the controller's topology. These nodes + are translated by the driver's .xlate() function. + +Required properties (port (child) node): +- #phy-cells : Should be 1 (See second example) + Cell after port phandle is device type from: + - MIPHY_TYPE_SATA + - MIPHY_TYPE_PCI +- reg : Address and length of register sets for each device in + "reg-names" +- reg-names : The names of the register addresses corresponding to the + registers filled in "reg": + - sata: For SATA devices + - pcie: For PCIe devices + - syscfg: To specify the syscfg based config register + +Optional properties (port (child) node): +- st,sata-gen : Generation of locally attached SATA IP. Expected values + are {1,2,3). If not supplied generation 1 hardware will + be expected +- st,pcie-tx-pol-inv : Bool property to invert the polarity PCIe Tx (Txn/Txp) +- st,sata-tx-pol-inv : Bool property to invert the polarity SATA Tx (Txn/Txp) + +Example: + + miphy365x_phy: miphy365x@fe382000 { + compatible = "st,miphy365x-phy"; + st,syscfg = <&syscfg_rear>; + #address-cells = <1>; + #size-cells = <1>; + ranges; + + phy_port0: port@fe382000 { + reg = <0xfe382000 0x100>, <0xfe394000 0x100>, <0x824 0x4>; + reg-names = "sata", "pcie", "syscfg"; + #phy-cells = <1>; + st,sata-gen = <3>; + }; + + phy_port1: port@fe38a000 { + reg = <0xfe38a000 0x100>, <0xfe804000 0x100>, <0x828 0x4>;; + reg-names = "sata", "pcie", "syscfg"; + #phy-cells = <1>; + st,pcie-tx-pol-inv; + }; + }; + +Specifying phy control of devices +================================= + +Device nodes should specify the configuration required in their "phys" +property, containing a phandle to the phy port node and a device type. + +Example: + +#include <dt-bindings/phy/phy-miphy365x.h> + + sata0: sata@fe380000 { + ... + phys = <&phy_port0 MIPHY_TYPE_SATA>; + ... + }; diff --git a/Documentation/devicetree/bindings/phy/qcom-apq8064-sata-phy.txt b/Documentation/devicetree/bindings/phy/qcom-apq8064-sata-phy.txt new file mode 100644 index 000000000000..952f6c96bab9 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/qcom-apq8064-sata-phy.txt @@ -0,0 +1,24 @@ +Qualcomm APQ8064 SATA PHY Controller +------------------------------------ + +SATA PHY nodes are defined to describe on-chip SATA Physical layer controllers. +Each SATA PHY controller should have its own node. + +Required properties: +- compatible: compatible list, contains "qcom,apq8064-sata-phy". +- reg: offset and length of the SATA PHY register set; +- #phy-cells: must be zero +- clocks: a list of phandles and clock-specifier pairs, one for each entry in + clock-names. +- clock-names: must be "cfg" for phy config clock. + +Example: + sata_phy: sata-phy@1b400000 { + compatible = "qcom,apq8064-sata-phy"; + reg = <0x1b400000 0x200>; + + clocks = <&gcc SATA_PHY_CFG_CLK>; + clock-names = "cfg"; + + #phy-cells = <0>; + }; diff --git a/Documentation/devicetree/bindings/phy/qcom-ipq806x-sata-phy.txt b/Documentation/devicetree/bindings/phy/qcom-ipq806x-sata-phy.txt new file mode 100644 index 000000000000..76bfbd056202 --- /dev/null +++ b/Documentation/devicetree/bindings/phy/qcom-ipq806x-sata-phy.txt @@ -0,0 +1,23 @@ +Qualcomm IPQ806x SATA PHY Controller +------------------------------------ + +SATA PHY nodes are defined to describe on-chip SATA Physical layer controllers. +Each SATA PHY controller should have its own node. + +Required properties: +- compatible: compatible list, contains "qcom,ipq806x-sata-phy" +- reg: offset and length of the SATA PHY register set; +- #phy-cells: must be zero +- clocks: must be exactly one entry +- clock-names: must be "cfg" + +Example: + sata_phy: sata-phy@1b400000 { + compatible = "qcom,ipq806x-sata-phy"; + reg = <0x1b400000 0x200>; + + clocks = <&gcc SATA_PHY_CFG_CLK>; + clock-names = "cfg"; + + #phy-cells = <0>; + }; diff --git a/Documentation/devicetree/bindings/phy/samsung-phy.txt b/Documentation/devicetree/bindings/phy/samsung-phy.txt index 2049261d8c31..6099a5c94283 100644 --- a/Documentation/devicetree/bindings/phy/samsung-phy.txt +++ b/Documentation/devicetree/bindings/phy/samsung-phy.txt @@ -26,6 +26,7 @@ Samsung S5P/EXYNOS SoC series USB PHY Required properties: - compatible : should be one of the listed compatibles: + - "samsung,exynos3250-usb2-phy" - "samsung,exynos4210-usb2-phy" - "samsung,exynos4x12-usb2-phy" - "samsung,exynos5250-usb2-phy" @@ -46,6 +47,7 @@ and Exynos 4212) it is as follows: 1 - USB host ("host"), 2 - HSIC0 ("hsic0"), 3 - HSIC1 ("hsic1"), +Exynos3250 has only USB device phy available as phy 0. Exynos 4210 and Exynos 4212 use mode switching and require that mode switch register is supplied. diff --git a/Documentation/devicetree/bindings/phy/ti-phy.txt b/Documentation/devicetree/bindings/phy/ti-phy.txt index 9ce458f32945..305e3df3d9b1 100644 --- a/Documentation/devicetree/bindings/phy/ti-phy.txt +++ b/Documentation/devicetree/bindings/phy/ti-phy.txt @@ -9,15 +9,17 @@ Required properties: e.g. USB2_PHY on OMAP5. "ti,control-phy-pipe3" - if it has DPLL and individual Rx & Tx power control e.g. USB3 PHY and SATA PHY on OMAP5. + "ti,control-phy-pcie" - for pcie to support external clock for pcie and to + set PCS delay value. + e.g. PCIE PHY in DRA7x "ti,control-phy-usb2-dra7" - if it has power down register like USB2 PHY on DRA7 platform. "ti,control-phy-usb2-am437" - if it has power down register like USB2 PHY on AM437 platform. - - reg : Address and length of the register set for the device. It contains - the address of "otghs_control" for control-phy-otghs or "power" register - for other types. - - reg-names: should be "otghs_control" control-phy-otghs and "power" for - other types. + - reg : register ranges as listed in the reg-names property + - reg-names: "otghs_control" for control-phy-otghs + "power", "pcie_pcs" and "control_sma" for control-phy-pcie + "power" for all other types omap_control_usb: omap-control-usb@4a002300 { compatible = "ti,control-phy-otghs"; @@ -56,8 +58,8 @@ usb2phy@4a0ad080 { TI PIPE3 PHY Required properties: - - compatible: Should be "ti,phy-usb3" or "ti,phy-pipe3-sata". - "ti,omap-usb3" is deprecated. + - compatible: Should be "ti,phy-usb3", "ti,phy-pipe3-sata" or + "ti,phy-pipe3-pcie. "ti,omap-usb3" is deprecated. - reg : Address and length of the register set for the device. - reg-names: The names of the register addresses corresponding to the registers filled in "reg". @@ -69,10 +71,17 @@ Required properties: * "wkupclk" - wakeup clock. * "sysclk" - system clock. * "refclk" - reference clock. + * "dpll_ref" - external dpll ref clk + * "dpll_ref_m2" - external dpll ref clk + * "phy-div" - divider for apll + * "div-clk" - apll clock Optional properties: - ctrl-module : phandle of the control module used by PHY driver to power on the PHY. + - id: If there are multiple instance of the same type, in order to + differentiate between each instance "id" can be used (e.g., multi-lane PCIe + PHY). If "id" is not provided, it is set to default value of '1'. This is usually a subnode of ocp2scp to which it is connected. diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-imx.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-imx.txt index a6a32cb7f777..1bae71e9ad47 100644 --- a/Documentation/devicetree/bindings/usb/ci-hdrc-imx.txt +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-imx.txt @@ -4,6 +4,7 @@ Required properties: - compatible: Should be "fsl,imx27-usb" - reg: Should contain registers location and length - interrupts: Should contain controller interrupt +- fsl,usbphy: phandle of usb phy that connects to the port Recommended properies: - phy_type: the type of the phy connected to the core. Should be one @@ -12,7 +13,6 @@ Recommended properies: - dr_mode: One of "host", "peripheral" or "otg". Defaults to "otg" Optional properties: -- fsl,usbphy: phandler of usb phy that connects to the only one port - fsl,usbmisc: phandler of non-core register device, with one argument that indicate usb controller index - vbus-supply: regulator for vbus diff --git a/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt b/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt index ba797d3e6326..c9205fbf26e2 100644 --- a/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt +++ b/Documentation/devicetree/bindings/usb/nvidia,tegra20-usb-phy.txt @@ -20,6 +20,12 @@ Required properties : Present if phy_type == utmi. - ulpi-link: The clock Tegra provides to the ULPI PHY (cdev2). Present if phy_type == ulpi, and ULPI link mode is in use. + - resets : Must contain an entry for each entry in reset-names. + See ../reset/reset.txt for details. + - reset-names : Must include the following entries: + - usb: The PHY's own reset signal. + - utmi-pads: The reset of the PHY containing the chip-wide UTMI pad control + registers. Required even if phy_type == ulpi. Required properties for phy_type == ulpi: - nvidia,phy-reset-gpio : The GPIO used to reset the PHY. @@ -56,6 +62,8 @@ Optional properties: host means this is a host controller peripheral means it is device controller otg means it can operate as either ("on the go") + - nvidia,has-utmi-pad-registers : boolean indicates whether this controller + contains the UTMI pad control registers common to all USB controllers. VBUS control (required for dr_mode == otg, optional for dr_mode == host): - vbus-supply: regulator for VBUS diff --git a/Documentation/devicetree/bindings/usb/usb-xhci.txt b/Documentation/devicetree/bindings/usb/usb-xhci.txt index 5a79377c6a96..86f67f0886bc 100644 --- a/Documentation/devicetree/bindings/usb/usb-xhci.txt +++ b/Documentation/devicetree/bindings/usb/usb-xhci.txt @@ -9,8 +9,9 @@ Required properties: register set for the device. - interrupts: one XHCI interrupt should be described here. -Optional property: +Optional properties: - clocks: reference to a clock + - usb3-lpm-capable: determines if platform is USB3 LPM capable Example: usb@f0931000 { diff --git a/Documentation/phy.txt b/Documentation/phy.txt index ebff6ee52441..c6594af94d25 100644 --- a/Documentation/phy.txt +++ b/Documentation/phy.txt @@ -53,10 +53,12 @@ unregister the PHY. The PHY driver should create the PHY in order for other peripheral controllers to make use of it. The PHY framework provides 2 APIs to create the PHY. -struct phy *phy_create(struct device *dev, const struct phy_ops *ops, - struct phy_init_data *init_data); -struct phy *devm_phy_create(struct device *dev, const struct phy_ops *ops, - struct phy_init_data *init_data); +struct phy *phy_create(struct device *dev, struct device_node *node, + const struct phy_ops *ops, + struct phy_init_data *init_data); +struct phy *devm_phy_create(struct device *dev, struct device_node *node, + const struct phy_ops *ops, + struct phy_init_data *init_data); The PHY drivers can use one of the above 2 APIs to create the PHY by passing the device pointer, phy ops and init_data. diff --git a/Documentation/usb/hotplug.txt b/Documentation/usb/hotplug.txt index 6424b130485c..a80b0e9a7a0b 100644 --- a/Documentation/usb/hotplug.txt +++ b/Documentation/usb/hotplug.txt @@ -105,13 +105,13 @@ macros such as these, and use driver_info to store more information. A short example, for a driver that supports several specific USB devices and their quirks, might have a MODULE_DEVICE_TABLE like this: - static const struct usb_device_id mydriver_id_table = { + static const struct usb_device_id mydriver_id_table[] = { { USB_DEVICE (0x9999, 0xaaaa), driver_info: QUIRK_X }, { USB_DEVICE (0xbbbb, 0x8888), driver_info: QUIRK_Y|QUIRK_Z }, ... { } /* end with an all-zeroes entry */ - } - MODULE_DEVICE_TABLE (usb, mydriver_id_table); + }; + MODULE_DEVICE_TABLE(usb, mydriver_id_table); Most USB device drivers should pass these tables to the USB subsystem as well as to the module management subsystem. Not all, though: some driver @@ -134,7 +134,7 @@ something like this: if exposing any operations through usbdevfs: .ioctl = my_ioctl, */ - } + }; When the USB subsystem knows about a driver's device ID table, it's used when choosing drivers to probe(). The thread doing new device processing checks diff --git a/Documentation/usb/power-management.txt b/Documentation/usb/power-management.txt index 1392b61d6ebe..7b90fe034c4b 100644 --- a/Documentation/usb/power-management.txt +++ b/Documentation/usb/power-management.txt @@ -2,8 +2,27 @@ Alan Stern <stern@rowland.harvard.edu> - October 28, 2010 - + Last-updated: February 2014 + + + Contents: + --------- + * What is Power Management? + * What is Remote Wakeup? + * When is a USB device idle? + * Forms of dynamic PM + * The user interface for dynamic PM + * Changing the default idle-delay time + * Warnings + * The driver interface for Power Management + * The driver interface for autosuspend and autoresume + * Other parts of the driver interface + * Mutual exclusion + * Interaction between dynamic PM and system PM + * xHCI hardware link PM + * USB Port Power Control + * User Interface for Port Power Control + * Suggested Userspace Port Power Policy What is Power Management? @@ -516,3 +535,225 @@ relevant attribute files is usb2_hardware_lpm. driver will enable hardware LPM for the device. You can write y/Y/1 or n/N/0 to the file to enable/disable USB2 hardware LPM manually. This is for test purpose mainly. + + + USB Port Power Control + ---------------------- + +In addition to suspending endpoint devices and enabling hardware +controlled link power management, the USB subsystem also has the +capability to disable power to ports under some conditions. Power is +controlled through Set/ClearPortFeature(PORT_POWER) requests to a hub. +In the case of a root or platform-internal hub the host controller +driver translates PORT_POWER requests into platform firmware (ACPI) +method calls to set the port power state. For more background see the +Linux Plumbers Conference 2012 slides [1] and video [2]: + +Upon receiving a ClearPortFeature(PORT_POWER) request a USB port is +logically off, and may trigger the actual loss of VBUS to the port [3]. +VBUS may be maintained in the case where a hub gangs multiple ports into +a shared power well causing power to remain until all ports in the gang +are turned off. VBUS may also be maintained by hub ports configured for +a charging application. In any event a logically off port will lose +connection with its device, not respond to hotplug events, and not +respond to remote wakeup events*. + +WARNING: turning off a port may result in the inability to hot add a device. +Please see "User Interface for Port Power Control" for details. + +As far as the effect on the device itself it is similar to what a device +goes through during system suspend, i.e. the power session is lost. Any +USB device or driver that misbehaves with system suspend will be +similarly affected by a port power cycle event. For this reason the +implementation shares the same device recovery path (and honors the same +quirks) as the system resume path for the hub. + +[1]: http://dl.dropbox.com/u/96820575/sarah-sharp-lpt-port-power-off2-mini.pdf +[2]: http://linuxplumbers.ubicast.tv/videos/usb-port-power-off-kerneluserspace-api/ +[3]: USB 3.1 Section 10.12 +* wakeup note: if a device is configured to send wakeup events the port + power control implementation will block poweroff attempts on that + port. + + + User Interface for Port Power Control + ------------------------------------- + +The port power control mechanism uses the PM runtime system. Poweroff is +requested by clearing the power/pm_qos_no_power_off flag of the port device +(defaults to 1). If the port is disconnected it will immediately receive a +ClearPortFeature(PORT_POWER) request. Otherwise, it will honor the pm runtime +rules and require the attached child device and all descendants to be suspended. +This mechanism is dependent on the hub advertising port power switching in its +hub descriptor (wHubCharacteristics logical power switching mode field). + +Note, some interface devices/drivers do not support autosuspend. Userspace may +need to unbind the interface drivers before the usb_device will suspend. An +unbound interface device is suspended by default. When unbinding, be careful +to unbind interface drivers, not the driver of the parent usb device. Also, +leave hub interface drivers bound. If the driver for the usb device (not +interface) is unbound the kernel is no longer able to resume the device. If a +hub interface driver is unbound, control of its child ports is lost and all +attached child-devices will disconnect. A good rule of thumb is that if the +'driver/module' link for a device points to /sys/module/usbcore then unbinding +it will interfere with port power control. + +Example of the relevant files for port power control. Note, in this example +these files are relative to a usb hub device (prefix). + + prefix=/sys/devices/pci0000:00/0000:00:14.0/usb3/3-1 + + attached child device + + hub port device + | + hub interface device + | | + v v v + $prefix/3-1:1.0/3-1-port1/device + + $prefix/3-1:1.0/3-1-port1/power/pm_qos_no_power_off + $prefix/3-1:1.0/3-1-port1/device/power/control + $prefix/3-1:1.0/3-1-port1/device/3-1.1:<intf0>/driver/unbind + $prefix/3-1:1.0/3-1-port1/device/3-1.1:<intf1>/driver/unbind + ... + $prefix/3-1:1.0/3-1-port1/device/3-1.1:<intfN>/driver/unbind + +In addition to these files some ports may have a 'peer' link to a port on +another hub. The expectation is that all superspeed ports have a +hi-speed peer. + +$prefix/3-1:1.0/3-1-port1/peer -> ../../../../usb2/2-1/2-1:1.0/2-1-port1 +../../../../usb2/2-1/2-1:1.0/2-1-port1/peer -> ../../../../usb3/3-1/3-1:1.0/3-1-port1 + +Distinct from 'companion ports', or 'ehci/xhci shared switchover ports' +peer ports are simply the hi-speed and superspeed interface pins that +are combined into a single usb3 connector. Peer ports share the same +ancestor XHCI device. + +While a superspeed port is powered off a device may downgrade its +connection and attempt to connect to the hi-speed pins. The +implementation takes steps to prevent this: + +1/ Port suspend is sequenced to guarantee that hi-speed ports are powered-off + before their superspeed peer is permitted to power-off. The implication is + that the setting pm_qos_no_power_off to zero on a superspeed port may not cause + the port to power-off until its highspeed peer has gone to its runtime suspend + state. Userspace must take care to order the suspensions if it wants to + guarantee that a superspeed port will power-off. + +2/ Port resume is sequenced to force a superspeed port to power-on prior to its + highspeed peer. + +3/ Port resume always triggers an attached child device to resume. After a + power session is lost the device may have been removed, or need reset. + Resuming the child device when the parent port regains power resolves those + states and clamps the maximum port power cycle frequency at the rate the child + device can suspend (autosuspend-delay) and resume (reset-resume latency). + +Sysfs files relevant for port power control: + <hubdev-portX>/power/pm_qos_no_power_off: + This writable flag controls the state of an idle port. + Once all children and descendants have suspended the + port may suspend/poweroff provided that + pm_qos_no_power_off is '0'. If pm_qos_no_power_off is + '1' the port will remain active/powered regardless of + the stats of descendants. Defaults to 1. + + <hubdev-portX>/power/runtime_status: + This file reflects whether the port is 'active' (power is on) + or 'suspended' (logically off). There is no indication to + userspace whether VBUS is still supplied. + + <hubdev-portX>/connect_type: + An advisory read-only flag to userspace indicating the + location and connection type of the port. It returns + one of four values 'hotplug', 'hardwired', 'not used', + and 'unknown'. All values, besides unknown, are set by + platform firmware. + + "hotplug" indicates an externally connectable/visible + port on the platform. Typically userspace would choose + to keep such a port powered to handle new device + connection events. + + "hardwired" refers to a port that is not visible but + connectable. Examples are internal ports for USB + bluetooth that can be disconnected via an external + switch or a port with a hardwired USB camera. It is + expected to be safe to allow these ports to suspend + provided pm_qos_no_power_off is coordinated with any + switch that gates connections. Userspace must arrange + for the device to be connected prior to the port + powering off, or to activate the port prior to enabling + connection via a switch. + + "not used" refers to an internal port that is expected + to never have a device connected to it. These may be + empty internal ports, or ports that are not physically + exposed on a platform. Considered safe to be + powered-off at all times. + + "unknown" means platform firmware does not provide + information for this port. Most commonly refers to + external hub ports which should be considered 'hotplug' + for policy decisions. + + NOTE1: since we are relying on the BIOS to get this ACPI + information correct, the USB port descriptions may be + missing or wrong. + + NOTE2: Take care in clearing pm_qos_no_power_off. Once + power is off this port will + not respond to new connect events. + + Once a child device is attached additional constraints are + applied before the port is allowed to poweroff. + + <child>/power/control: + Must be 'auto', and the port will not + power down until <child>/power/runtime_status + reflects the 'suspended' state. Default + value is controlled by child device driver. + + <child>/power/persist: + This defaults to '1' for most devices and indicates if + kernel can persist the device's configuration across a + power session loss (suspend / port-power event). When + this value is '0' (quirky devices), port poweroff is + disabled. + + <child>/driver/unbind: + Wakeup capable devices will block port poweroff. At + this time the only mechanism to clear the usb-internal + wakeup-capability for an interface device is to unbind + its driver. + +Summary of poweroff pre-requisite settings relative to a port device: + + echo 0 > power/pm_qos_no_power_off + echo 0 > peer/power/pm_qos_no_power_off # if it exists + echo auto > power/control # this is the default value + echo auto > <child>/power/control + echo 1 > <child>/power/persist # this is the default value + + Suggested Userspace Port Power Policy + ------------------------------------- + +As noted above userspace needs to be careful and deliberate about what +ports are enabled for poweroff. + +The default configuration is that all ports start with +power/pm_qos_no_power_off set to '1' causing ports to always remain +active. + +Given confidence in the platform firmware's description of the ports +(ACPI _PLD record for a port populates 'connect_type') userspace can +clear pm_qos_no_power_off for all 'not used' ports. The same can be +done for 'hardwired' ports provided poweroff is coordinated with any +connection switch for the port. + +A more aggressive userspace policy is to enable USB port power off for +all ports (set <hubdev-portX>/power/pm_qos_no_power_off to '0') when +some external factor indicates the user has stopped interacting with the +system. For example, a distro may want to enable power off all USB +ports when the screen blanks, and re-power them when the screen becomes +active. Smart phones and tablets may want to power off USB ports when +the user pushes the power button. |