BMC/Intel-BMC/linux.git/drivers/usb/core/hub.h, branch dev-5.2

usb: hub: add retry routine after intr URB submit error

2019-01-18T08:58:04+00:00

The hub sends hot-plug events to the host trough it's interrupt URB. The driver takes care of completing the URB and re-submitting it. Completion errors are handled in the hub_event() work, yet submission errors are ignored, rendering the device unresponsive. All further events are lost. It is fairly hard to find this issue in the wild, since you have to time the USB hot-plug event with the URB submission failure. For instance it could be the system running out of memory or some malfunction in the USB controller driver. Nevertheless, it's pretty reasonable to think it'll happen sometime. One can trigger this issue using eBPF's function override feature (see BCC's inject.py script). This patch adds a retry routine to the event of a submission error. The HUB driver will try to re-submit the URB once every second until it's successful or the HUB is disconnected. As some USB subsystems already take care of this issue, the implementation was inspired from usbhid/hid_core.c's. Signed-off-by: Nicolas Saenz Julienne Reviewed-by: Oliver Neukum Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

usb: hub: Per-port setting to use old enumeration scheme

2018-05-31T10:48:17+00:00

The "old" enumeration scheme is considerably faster (it takes ~244ms instead of ~356ms to get the descriptor). It is currently only possible to use the old scheme globally (/sys/module/usbcore/parameters/old_scheme_first), which is not desirable as the new scheme was introduced to increase compatibility with more devices. However, in our case, we care about time-to-active for a specific USB device (which we make the firmware for), on a specific port (that is pogo-pin based: not a standard USB port). This new sysfs option makes it possible to use the old scheme on a single port only. Signed-off-by: Nicolas Boichat Signed-off-by: Greg Kroah-Hartman

usb: core: introduce per-port over-current counters

2018-03-22T12:07:05+00:00

For some userspace applications information on the number of over-current conditions at specific USB hub ports is relevant. In our case we have a series of USB hardware (using the cp210x driver) which communicates using a proprietary protocol. These devices sometimes trigger an over-current situation on some hubs. In case of such an over-current situation the USB devices offer an interface for reducing the max used power. As these conditions are quite rare and imply performance reductions of the device we don't want to reduce the max power always. Therefore give user-space applications the possibility to react adequately by introducing an over_current_counter in the usb port struct which is exported via sysfs. Signed-off-by: Richard Leitner Signed-off-by: Greg Kroah-Hartman

USB: core: Remove redundant license text

2017-11-04T10:55:39+00:00

Now that the SPDX tag is in all USB files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Signed-off-by: Greg Kroah-Hartman Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

USB: add SPDX identifiers to all remaining files in drivers/usb/

2017-11-04T10:48:02+00:00

It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/usb/ and include/linux/usb* files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Thomas Gleixner Cc: Kate Stewart Cc: Philippe Ombredanne Signed-off-by: Greg Kroah-Hartman Acked-by: Felipe Balbi Acked-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman

usb: Support USB 3.1 extended port status request

2016-01-25T04:16:52+00:00

usb 3.1 extend the hub get-port-status request by adding different request types. the new request types return 4 additional bytes called extended port status, these bytes are returned after the regular portstatus and portchange values. The extended port status contains a speed ID for the currently used sublink speed. A table of supported Speed IDs with details about the link is provided by the hub in the device descriptor BOS SuperSpeedPlus device capability Sublink Speed Attributes. Support this new request. Ask for the extended port status after port reset if hub supports USB 3.1. If link is running at SuperSpeedPlus set the device speed to USB_SPEED_SUPER_PLUS Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman

usb: core: lpm: add sysfs node for usb3 lpm permit

2015-12-01T22:58:18+00:00

USB3 LPM is default on in Linux kernel if both xHCI host controller and the USB devices declare to be LPM-capable. Unfortunately, some devices are known to work well with LPM disabled, but to be broken if LPM is enabled, although it declares the LPM capability. Users won't be able to use this kind of devices, until someone puts them in the kernel blacklist and gets the kernel upgraded. This patch adds a sysfs node to permit or forbit USB3 LPM U1 or U2 entry for a port. The settings apply to both before and after device enumeration. Supported values are "0" - neither u1 nor u2 permitted, "u1" - only u1 is permitted, "u2" - only u2 is permitted, "u1_u2" - both u1 and u2 are permitted. With this interface, users can use an LPM-unfriendly USB device on a released Linux kernel. Signed-off-by: Lu Baolu Signed-off-by: Zhuang Jin Can Signed-off-by: Greg Kroah-Hartman

usb: hub: convert khubd into workqueue

2014-09-24T05:33:19+00:00

There is no need to have separate kthread for handling USB hub events. It is more elegant to use the workqueue framework. The workqueue is allocated as freezable because the original thread was freezable as well. Also it is allocated as ordered because the code is not ready for parallel processing of hub events, see choose_devnum(). struct usb_hub is passed via the work item. Therefore we do not need hub_event_list. Also hub_thread() is not longer needed. It would call only hub_event(). The rest of the code did manipulate the kthread and it is handled by the workqueue framework now. kick_khubd is renamed to kick_hub_wq() to make the function clear. And the protection against races is done another way, see below. hub_event_lock has been removed. It cannot longer be used to protect struct usb_hub between hub_event() and hub_disconnect(). Instead we need to get hub->kref already in kick_hub_wq(). The lock is not really needed for the other scenarios as well. queue_work() returns whether it succeeded. We could revert the needed operations accordingly. This is enough to avoid duplicity and inconsistencies. Yes, the removed lock causes that there is not longer such a strong synchronization between scheduling the work and manipulating hub->disconnected. But kick_hub_wq() must never be called together with hub_disconnect() otherwise even the original code would have failed. Any callers are responsible for this. Therefore the only problem is that hub_disconnect() could be called in parallel with hub_event(). But this was possible even in the past. struct usb_hub is still guarded by hub->kref and released in hub_events() when needed. Note that the source file is still full of the obsolete "khubd" strings. Let's remove them in a follow up patch. This patch already is complex enough. Thanks a lot Alan Stern for code review, many useful tips and guidance. Also thanks to Tejun Heo for hints how to allocate the workqueue. Signed-off-by: Petr Mladek Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

usb: force warm reset to break link re-connect livelock

2014-07-09T22:43:12+00:00

Resuming a powered down port sometimes results in the port state being stuck in the training sequence. hub 3-0:1.0: debounce: port 1: total 2000ms stable 0ms status 0x2e0 port1: can't get reconnection after setting port power on, status -110 hub 3-0:1.0: port 1 status 0000.02e0 after resume, -19 usb 3-1: can't resume, status -19 hub 3-0:1.0: logical disconnect on port 1 In the case above we wait for the port re-connect timeout of 2 seconds and observe that the port status is USB_SS_PORT_LS_POLLING (although it is likely toggling between this state and USB_SS_PORT_LS_RX_DETECT). This is indicative of a case where the device is failing to progress the link training state machine. It is resolved by issuing a warm reset to get the hub and device link state machines back in sync. hub 3-0:1.0: debounce: port 1: total 2000ms stable 0ms status 0x2e0 usb usb3: port1 usb_port_runtime_resume requires warm reset hub 3-0:1.0: port 1 not warm reset yet, waiting 50ms usb 3-1: reset SuperSpeed USB device number 2 using xhci_hcd After a reconnect timeout when we expect the device to be present, force a warm reset of the device. Note that we can not simply look at the link status to determine if a warm reset is required as any of the training states USB_SS_PORT_LS_POLLING, USB_SS_PORT_LS_RX_DETECT, or USB_SS_PORT_LS_COMP_MOD are valid states that do not indicate the need for warm reset by themselves. Cc: Alan Stern Cc: Kukjin Kim Cc: Vincent Palatin Cc: Lan Tianyu Cc: Ksenia Ragiadakou Cc: Vivek Gautam Cc: Douglas Anderson Cc: Felipe Balbi Cc: Sunil Joshi Cc: Hans de Goede Acked-by: Julius Werner Signed-off-by: Dan Williams Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman

usb: fix hub-port pm_runtime_enable() vs runtime pm transitions

2014-06-18T00:04:39+00:00

Commit 9262c19d14c4 "usb: disable port power control if not supported in wHubCharacteristics" gated enabling runtime pm for usb_port devices on whether the parent hub supports power control, which causes a regression. The port must still be allowed to carry out runtime pm callbacks and receive a -EAGAIN or -EBUSY result. Otherwise the usb_port device will transition to the pm error state and trigger the same for the child usb_device. Prior to the offending commit usb_hub_create_port_device() arranged for runtime pm to be disabled is dev_pm_qos_expose_flags() failed. Instead, force the default state of PM_QOS_FLAG_NO_POWER_OFF flag to be set prior to enabling runtime pm. If that policy can not be set then fail registration. Report: http://marc.info/?l=linux-usb&m=140290586301336&w=2 Fixes: 9262c19d14c4 ("usb: disable port power control if not supported in wHubCharacteristics") Reported-by: Bjørn Mork Reported-by: Alan Stern Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman