delta/linux.git/include/linux/usb/hcd.h, branch proc-cmdline git.kernel.org: pub/scm/linux/kernel/git/torvalds/linux.git usb: core: hcd: remove support for initializing a single PHY 2018-03-09T17:43:53+00:00 Martin Blumenstingl martin.blumenstingl@googlemail.com 2018-03-03T21:43:09+00:00 ad70f937e9d0bdc580e390db3a047f9e58863b6e With the new PHY wrapper in place we can now handle multiple PHYs. Remove the code which handles only one generic PHY as this is now covered (with support for multiple PHYs as well as suspend/resume support) by the new PHY wrapper. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Tested-by: Neil Armstrong <narmstrong@baylibre.con> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
With the new PHY wrapper in place we can now handle multiple PHYs.
Remove the code which handles only one generic PHY as this is now
covered (with support for multiple PHYs as well as suspend/resume
support) by the new PHY wrapper.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Neil Armstrong <narmstrong@baylibre.con>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: core: hcd: integrate the PHY wrapper into the HCD core 2018-03-09T17:43:53+00:00 Martin Blumenstingl martin.blumenstingl@googlemail.com 2018-03-03T21:43:05+00:00 178a0bce05cbc17a27f9cba78258c5d12adc980c This integrates the PHY wrapper into the core hcd infrastructure. Multiple PHYs which are part of the HCD's device tree node are now managed (= powered on/off when needed), by the new usb_phy_roothub code. Suspend and resume is also supported, however not for runtime/auto-suspend (which is triggered for example when no devices are connected to the USB bus). This is needed on some SoCs (for example Amlogic Meson GXL) because if the PHYs are disabled during auto-suspend then devices which are plugged in afterwards are not seen by the host. One example where this is required is the Amlogic GXL and GXM SoCs: They are using a dwc3 USB controller with up to three ports enabled on the internal roothub. Each port has it's own PHY which must be enabled (if one of the PHYs is left disabled then none of the USB ports works at all). The new logic works on the Amlogic GXL and GXM SoCs because the dwc3 driver internally creates a xhci-hcd which then registers a HCD which then triggers our new PHY wrapper. USB controller drivers can opt out of this by setting "skip_phy_initialization" in struct usb_hcd to true. This is identical to how it works for a single USB PHY, so the "multiple PHY" handling is disabled for drivers that opted out of the management logic of a single PHY. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com> Tested-by: Yixun Lan <yixun.lan@amlogic.com> Tested-by: Neil Armstrong <narmstrong@baylibre.con> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This integrates the PHY wrapper into the core hcd infrastructure.
Multiple PHYs which are part of the HCD's device tree node are now
managed (= powered on/off when needed), by the new usb_phy_roothub code.

Suspend and resume is also supported, however not for
runtime/auto-suspend (which is triggered for example when no devices are
connected to the USB bus). This is needed on some SoCs (for example
Amlogic Meson GXL) because if the PHYs are disabled during auto-suspend
then devices which are plugged in afterwards are not seen by the host.

One example where this is required is the Amlogic GXL and GXM SoCs:
They are using a dwc3 USB controller with up to three ports enabled on
the internal roothub. Each port has it's own PHY which must be enabled
(if one of the PHYs is left disabled then none of the USB ports works at
all).
The new logic works on the Amlogic GXL and GXM SoCs because the dwc3
driver internally creates a xhci-hcd which then registers a HCD which
then triggers our new PHY wrapper.

USB controller drivers can opt out of this by setting
"skip_phy_initialization" in struct usb_hcd to true. This is identical
to how it works for a single USB PHY, so the "multiple PHY" handling is
disabled for drivers that opted out of the management logic of a single
PHY.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Tested-by: Yixun Lan <yixun.lan@amlogic.com>
Tested-by: Neil Armstrong <narmstrong@baylibre.con>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: add a flag to skip PHY initialization to struct usb_hcd 2018-03-09T17:43:52+00:00 Martin Blumenstingl martin.blumenstingl@googlemail.com 2018-03-03T21:43:03+00:00 4e88d4c083016454f179686529ae65d70b933b58 The USB HCD core driver parses the device-tree node for "phys" and "usb-phys" properties. It also manages the power state of these PHYs automatically. However, drivers may opt-out of this behavior by setting "phy" or "usb_phy" in struct usb_hcd to a non-null value. An example where this is required is the "Qualcomm USB2 controller", implemented by the chipidea driver. The hardware requires that the PHY is only powered on after the "reset completed" event from the controller is received. A follow-up patch will allow the USB HCD core driver to manage more than one PHY. Add a new "skip_phy_initialization" bitflag to struct usb_hcd so drivers can opt-out of any PHY management provided by the USB HCD core driver. This also updates the existing drivers so they use the new flag if they want to opt out of the PHY management provided by the USB HCD core driver. This means that for these drivers the new "multiple PHY" handling (which will be added in a follow-up patch) will be disabled as well. Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Acked-by: Peter Chen <peter.chen@nxp.com> Tested-by: Neil Armstrong <narmstrong@baylibre.con> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The USB HCD core driver parses the device-tree node for "phys" and
"usb-phys" properties. It also manages the power state of these PHYs
automatically.
However, drivers may opt-out of this behavior by setting "phy" or
"usb_phy" in struct usb_hcd to a non-null value. An example where this
is required is the "Qualcomm USB2 controller", implemented by the
chipidea driver. The hardware requires that the PHY is only powered on
after the "reset completed" event from the controller is received.

A follow-up patch will allow the USB HCD core driver to manage more than
one PHY. Add a new "skip_phy_initialization" bitflag to struct usb_hcd
so drivers can opt-out of any PHY management provided by the USB HCD
core driver.

This also updates the existing drivers so they use the new flag if they
want to opt out of the PHY management provided by the USB HCD core
driver. This means that for these drivers the new "multiple PHY"
handling (which will be added in a follow-up patch) will be disabled as
well.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Peter Chen <peter.chen@nxp.com>
Tested-by: Neil Armstrong <narmstrong@baylibre.con>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: add SPDX identifiers to all remaining files in drivers/usb/ 2017-11-04T10:48:02+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2017-11-03T10:28:30+00:00 5fd54ace4721fc5ce2bb5aef6318fcf17f421460 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 <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Acked-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
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 <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: Fix typo in the definition of Endpoint[out]Request 2017-06-13T08:48:24+00:00 Benjamin Herrenschmidt benh@kernel.crashing.org 2017-06-13T06:01:13+00:00 7cf916bd639bd26db7214f2205bccdb4b9306256 The current definition is wrong. This breaks my upcoming Aspeed virtual hub driver. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The current definition is wrong. This breaks my upcoming
Aspeed virtual hub driver.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: host: xhci-ring: don't need to clear interrupt pending for MSI enabled hcd 2017-05-18T13:19:41+00:00 Peter Chen peter.chen@nxp.com 2017-05-17T15:32:02+00:00 6a29beef9d1b16c762e469d77e28c3de3f5c3dbb According to xHCI spec Figure 30: Interrupt Throttle Flow Diagram If PCI Message Signaled Interrupts (MSI or MSI-X) are enabled, then the assertion of the Interrupt Pending (IP) flag in Figure 30 generates a PCI Dword write. The IP flag is automatically cleared by the completion of the PCI write. the MSI enabled HCs don't need to clear interrupt pending bit, but hcd->irq = 0 doesn't equal to MSI enabled HCD. At some Dual-role controller software designs, it sets hcd->irq as 0 to avoid HCD requesting interrupt, and they want to decide when to call usb_hcd_irq by software. Signed-off-by: Peter Chen <peter.chen@nxp.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
According to xHCI spec Figure 30: Interrupt Throttle Flow Diagram

	If PCI Message Signaled Interrupts (MSI or MSI-X) are enabled,
       	then the assertion of the Interrupt Pending (IP) flag in Figure 30
       	generates a PCI Dword write. The IP flag is automatically cleared
       	by the completion of the PCI write.

the MSI enabled HCs don't need to clear interrupt pending bit, but
hcd->irq = 0 doesn't equal to MSI enabled HCD. At some Dual-role
controller software designs, it sets hcd->irq as 0 to avoid HCD
requesting interrupt, and they want to decide when to call usb_hcd_irq
by software.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: separate out sysdev pointer from usb_bus 2017-03-23T07:20:21+00:00 Arnd Bergmann arnd@arndb.de 2017-03-13T02:18:41+00:00 a8c06e407ef969461b7f51ec72839fe382dd3c29 For xhci-hcd platform device, all the DMA parameters are not configured properly, notably dma ops for dwc3 devices. The idea here is that you pass in the parent of_node along with the child device pointer, so it would behave exactly like the parent already does. The difference is that it also handles all the other attributes besides the mask. sysdev will represent the physical device, as seen from firmware or bus.Splitting the usb_bus->controller field into the Linux-internal device (used for the sysfs hierarchy, for printks and for power management) and a new pointer (used for DMA, DT enumeration and phy lookup) probably covers all that we really need. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Sriram Dash <sriram.dash@nxp.com> Tested-by: Baolin Wang <baolin.wang@linaro.org> Tested-by: Brian Norris <briannorris@chromium.org> Tested-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Tested-by: Vivek Gautam <vivek.gautam@codeaurora.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Peter Chen <peter.chen@nxp.com> Cc: Felipe Balbi <felipe.balbi@linux.intel.com> Cc: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Sinjan Kumar <sinjank@codeaurora.org> Cc: David Fisher <david.fisher1@synopsys.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: "Thang Q. Nguyen" <tqnguyen@apm.com> Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Bjorn Andersson <bjorn.andersson@linaro.org> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Jon Masters <jcm@redhat.com> Cc: Dann Frazier <dann.frazier@canonical.com> Cc: Peter Chen <peter.chen@nxp.com> Cc: Leo Li <pku.leo@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
For xhci-hcd platform device, all the DMA parameters are not
configured properly, notably dma ops for dwc3 devices.

The idea here is that you pass in the parent of_node along with
the child device pointer, so it would behave exactly like the
parent already does. The difference is that it also handles all
the other attributes besides the mask.

sysdev will represent the physical device, as seen from firmware
or bus.Splitting the usb_bus->controller field into the
Linux-internal device (used for the sysfs hierarchy, for printks
and for power management) and a new pointer (used for DMA,
DT enumeration and phy lookup) probably covers all that we really
need.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
Tested-by: Baolin Wang <baolin.wang@linaro.org>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Tested-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Cc: Sinjan Kumar <sinjank@codeaurora.org>
Cc: David Fisher <david.fisher1@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "Thang Q. Nguyen" <tqnguyen@apm.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Ming Lei <tom.leiming@gmail.com>
Cc: Jon Masters <jcm@redhat.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Peter Chen <peter.chen@nxp.com>
Cc: Leo Li <pku.leo@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: add CONFIG_USB_PCI for system have both PCI HW and non-PCI based USB HW 2017-03-17T04:16:56+00:00 yuan linyu Linyu.Yuan@alcatel-sbell.com.cn 2017-02-25T11:20:55+00:00 2c93e790e8253552227bf9b46a8d49dca3f71b06 a lot of embeded system SOC (e.g. freescale T2080) have both PCI and USB modules. But USB module is controlled by registers directly, it have no relationship with PCI module. when say N here it will not build PCI related code in USB driver. Signed-off-by: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn> Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
a lot of embeded system SOC (e.g. freescale T2080) have both
PCI and USB modules. But USB module is controlled by registers directly,
it have no relationship with PCI module.

when say N here it will not build PCI related code in USB driver.

Signed-off-by: yuan linyu <Linyu.Yuan@alcatel-sbell.com.cn>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: hcd.h: construct hub class request constants from simpler constants 2016-12-05T15:37:10+00:00 Tal Shorer tal.shorer@gmail.com 2016-11-18T12:17:26+00:00 b9c2a2a39898d55b9fe13aa1fe15891e37bc9087 Currently, each hub class request constant is defined by a line like: #define ClearHubFeature (0x2000 | USB_REQ_CLEAR_FEATURE) The "magic" number for the high byte is one of 0x20, 0xa0, 0x23, 0xa3. The 0x80 bit that changes inditace USB_DIR_IN, and the 0x03 that pops up is the difference between USB_RECIP_DEVICE (0x00) and USB_RECIP_OTHER (0x03). The constant 0x20 bit is USB_TYPE_CLASS. This patch eliminates those magic numbers by defining a macro to help construct these hub class request from simpler constants. Note that USB_RT_HUB is defined as (USB_TYPE_CLASS | USB_RECIP_DEVICE) and that USB_RT_PORT is defined as (USB_TYPE_CLASS | USB_RECIP_OTHER). Signed-off-by: Tal Shorer <tal.shorer@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
Currently, each hub class request constant is defined by a line like:
#define ClearHubFeature		(0x2000 | USB_REQ_CLEAR_FEATURE)

The "magic" number for the high byte is one of 0x20, 0xa0, 0x23, 0xa3.
The 0x80 bit that changes inditace USB_DIR_IN, and the 0x03 that
pops up is the difference between USB_RECIP_DEVICE (0x00) and
USB_RECIP_OTHER (0x03). The constant 0x20 bit is USB_TYPE_CLASS.

This patch eliminates those magic numbers by defining a macro to help
construct these hub class request from simpler constants.
Note that USB_RT_HUB is defined as (USB_TYPE_CLASS | USB_RECIP_DEVICE)
and that USB_RT_PORT is defined as (USB_TYPE_CLASS | USB_RECIP_OTHER).

Signed-off-by: Tal Shorer <tal.shorer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: core: hub: hub_port_init lock controller instead of bus 2016-04-28T19:40:46+00:00 Chris Bainbridge chris.bainbridge@gmail.com 2016-04-25T12:48:38+00:00 feb26ac31a2a5cb88d86680d9a94916a6343e9e6 The XHCI controller presents two USB buses to the system - one for USB2 and one for USB3. The hub init code (hub_port_init) is reentrant but only locks one bus per thread, leading to a race condition failure when two threads attempt to simultaneously initialise a USB2 and USB3 device: [ 8.034843] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command [ 13.183701] usb 3-3: device descriptor read/all, error -110 On a test system this failure occurred on 6% of all boots. The call traces at the point of failure are: Call Trace: [<ffffffff81b9bab7>] schedule+0x37/0x90 [<ffffffff817da7cd>] usb_kill_urb+0x8d/0xd0 [<ffffffff8111e5e0>] ? wake_up_atomic_t+0x30/0x30 [<ffffffff817dafbe>] usb_start_wait_urb+0xbe/0x150 [<ffffffff817db10c>] usb_control_msg+0xbc/0xf0 [<ffffffff817d07de>] hub_port_init+0x51e/0xb70 [<ffffffff817d4697>] hub_event+0x817/0x1570 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620 [<ffffffff810f4684>] worker_thread+0x64/0x4b0 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390 [<ffffffff810fa7f5>] kthread+0x105/0x120 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 Call Trace: [<ffffffff817fd36d>] xhci_setup_device+0x53d/0xa40 [<ffffffff817fd87e>] xhci_address_device+0xe/0x10 [<ffffffff817d047f>] hub_port_init+0x1bf/0xb70 [<ffffffff811247ed>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff817d4697>] hub_event+0x817/0x1570 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620 [<ffffffff810f4684>] worker_thread+0x64/0x4b0 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390 [<ffffffff810fa7f5>] kthread+0x105/0x120 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200 Which results from the two call chains: hub_port_init usb_get_device_descriptor usb_get_descriptor usb_control_msg usb_internal_control_msg usb_start_wait_urb usb_submit_urb / wait_for_completion_timeout / usb_kill_urb hub_port_init hub_set_address xhci_address_device xhci_setup_device Mathias Nyman explains the current behaviour violates the XHCI spec: hub_port_reset() will end up moving the corresponding xhci device slot to default state. As hub_port_reset() is called several times in hub_port_init() it sounds reasonable that we could end up with two threads having their xhci device slots in default state at the same time, which according to xhci 4.5.3 specs still is a big no no: "Note: Software shall not transition more than one Device Slot to the Default State at a time" So both threads fail at their next task after this. One fails to read the descriptor, and the other fails addressing the device. Fix this in hub_port_init by locking the USB controller (instead of an individual bus) to prevent simultaneous initialisation of both buses. Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel") Link: https://lkml.org/lkml/2016/2/8/312 Link: https://lkml.org/lkml/2016/2/4/748 Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com> Cc: stable <stable@vger.kernel.org> Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
The XHCI controller presents two USB buses to the system - one for USB2
and one for USB3. The hub init code (hub_port_init) is reentrant but
only locks one bus per thread, leading to a race condition failure when
two threads attempt to simultaneously initialise a USB2 and USB3 device:

[    8.034843] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command
[   13.183701] usb 3-3: device descriptor read/all, error -110

On a test system this failure occurred on 6% of all boots.

The call traces at the point of failure are:

Call Trace:
 [<ffffffff81b9bab7>] schedule+0x37/0x90
 [<ffffffff817da7cd>] usb_kill_urb+0x8d/0xd0
 [<ffffffff8111e5e0>] ? wake_up_atomic_t+0x30/0x30
 [<ffffffff817dafbe>] usb_start_wait_urb+0xbe/0x150
 [<ffffffff817db10c>] usb_control_msg+0xbc/0xf0
 [<ffffffff817d07de>] hub_port_init+0x51e/0xb70
 [<ffffffff817d4697>] hub_event+0x817/0x1570
 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
 [<ffffffff810f4684>] worker_thread+0x64/0x4b0
 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
 [<ffffffff810fa7f5>] kthread+0x105/0x120
 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200

Call Trace:
 [<ffffffff817fd36d>] xhci_setup_device+0x53d/0xa40
 [<ffffffff817fd87e>] xhci_address_device+0xe/0x10
 [<ffffffff817d047f>] hub_port_init+0x1bf/0xb70
 [<ffffffff811247ed>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff817d4697>] hub_event+0x817/0x1570
 [<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
 [<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
 [<ffffffff810f4684>] worker_thread+0x64/0x4b0
 [<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
 [<ffffffff810fa7f5>] kthread+0x105/0x120
 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
 [<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
 [<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200

Which results from the two call chains:

hub_port_init
 usb_get_device_descriptor
  usb_get_descriptor
   usb_control_msg
    usb_internal_control_msg
     usb_start_wait_urb
      usb_submit_urb / wait_for_completion_timeout / usb_kill_urb

hub_port_init
 hub_set_address
  xhci_address_device
   xhci_setup_device

Mathias Nyman explains the current behaviour violates the XHCI spec:

 hub_port_reset() will end up moving the corresponding xhci device slot
 to default state.

 As hub_port_reset() is called several times in hub_port_init() it
 sounds reasonable that we could end up with two threads having their
 xhci device slots in default state at the same time, which according to
 xhci 4.5.3 specs still is a big no no:

 "Note: Software shall not transition more than one Device Slot to the
  Default State at a time"

 So both threads fail at their next task after this.
 One fails to read the descriptor, and the other fails addressing the
 device.

Fix this in hub_port_init by locking the USB controller (instead of an
individual bus) to prevent simultaneous initialisation of both buses.

Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel")
Link: https://lkml.org/lkml/2016/2/8/312
Link: https://lkml.org/lkml/2016/2/4/748
Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>