<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/usb/core/hub.c, branch linux-5.2.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>usb: core: hub: Disable hub-initiated U1/U2</title>
<updated>2019-07-31T05:24:30+00:00</updated>
<author>
<name>Thinh Nguyen</name>
<email>Thinh.Nguyen@synopsys.com</email>
</author>
<published>2019-05-14T21:38:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2042746d87346e70e2c6c70537972616932b4207'/>
<id>2042746d87346e70e2c6c70537972616932b4207</id>
<content type='text'>
[ Upstream commit 561759292774707b71ee61aecc07724905bb7ef1 ]

If the device rejects the control transfer to enable device-initiated
U1/U2 entry, then the device will not initiate U1/U2 transition. To
improve the performance, the downstream port should not initate
transition to U1/U2 to avoid the delay from the device link command
response (no packet can be transmitted while waiting for a response from
the device). If the device has some quirks and does not implement U1/U2,
it may reject all the link state change requests, and the downstream
port may resend and flood the bus with more requests. This will affect
the device performance even further. This patch disables the
hub-initated U1/U2 if the device-initiated U1/U2 entry fails.

Reference: USB 3.2 spec 7.2.4.2.3

Signed-off-by: Thinh Nguyen &lt;thinhn@synopsys.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 561759292774707b71ee61aecc07724905bb7ef1 ]

If the device rejects the control transfer to enable device-initiated
U1/U2 entry, then the device will not initiate U1/U2 transition. To
improve the performance, the downstream port should not initate
transition to U1/U2 to avoid the delay from the device link command
response (no packet can be transmitted while waiting for a response from
the device). If the device has some quirks and does not implement U1/U2,
it may reject all the link state change requests, and the downstream
port may resend and flood the bus with more requests. This will affect
the device performance even further. This patch disables the
hub-initated U1/U2 if the device-initiated U1/U2 entry fails.

Reference: USB 3.2 spec 7.2.4.2.3

Signed-off-by: Thinh Nguyen &lt;thinhn@synopsys.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: Handle USB3 remote wakeup for LPM enabled devices correctly</title>
<updated>2019-07-26T07:11:10+00:00</updated>
<author>
<name>Lee, Chiasheng</name>
<email>chiasheng.lee@intel.com</email>
</author>
<published>2019-06-20T07:56:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3201a60323f05b3600c95f3d41778862b52b5e3b'/>
<id>3201a60323f05b3600c95f3d41778862b52b5e3b</id>
<content type='text'>
commit e244c4699f859cf7149b0781b1894c7996a8a1df upstream.

With Link Power Management (LPM) enabled USB3 links transition to low
power U1/U2 link states from U0 state automatically.

Current hub code detects USB3 remote wakeups by checking if the software
state still shows suspended, but the link has transitioned from suspended
U3 to enabled U0 state.

As it takes some time before the hub thread reads the port link state
after a USB3 wake notification, the link may have transitioned from U0
to U1/U2, and wake is not detected by hub code.

Fix this by handling U1/U2 states in the same way as U0 in USB3 wakeup
handling

This patch should be added to stable kernels since 4.13 where LPM was
kept enabled during suspend/resume

Cc: &lt;stable@vger.kernel.org&gt; # v4.13+
Signed-off-by: Lee, Chiasheng &lt;chiasheng.lee@intel.com&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e244c4699f859cf7149b0781b1894c7996a8a1df upstream.

With Link Power Management (LPM) enabled USB3 links transition to low
power U1/U2 link states from U0 state automatically.

Current hub code detects USB3 remote wakeups by checking if the software
state still shows suspended, but the link has transitioned from suspended
U3 to enabled U0 state.

As it takes some time before the hub thread reads the port link state
after a USB3 wake notification, the link may have transitioned from U0
to U1/U2, and wake is not detected by hub code.

Fix this by handling U1/U2 states in the same way as U0 in USB3 wakeup
handling

This patch should be added to stable kernels since 4.13 where LPM was
kept enabled during suspend/resume

Cc: &lt;stable@vger.kernel.org&gt; # v4.13+
Signed-off-by: Lee, Chiasheng &lt;chiasheng.lee@intel.com&gt;
Signed-off-by: Mathias Nyman &lt;mathias.nyman@linux.intel.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'usb-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-next</title>
<updated>2019-05-03T16:05:27+00:00</updated>
<author>
<name>Greg Kroah-Hartman</name>
<email>gregkh@linuxfoundation.org</email>
</author>
<published>2019-05-03T16:05:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3515468a87a47781f6af818773650513ff14656a'/>
<id>3515468a87a47781f6af818773650513ff14656a</id>
<content type='text'>
Felipe writes:

USB: changes for v5.2 merge window

With a total of 50 non-merge commits, this is not a large pull
request. Most of the changes are, again, in dwc2 (37%) and dwc3 (32%)
with the rest of it scattered among other UDCs, function drivers and
device-tree bindings.

No really big feature this time around apart from support to Amlogic
being added to both dwc3 and dwc2 drivers.

* tag 'usb-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb: (50 commits)
  usb: dwc3: Rename DWC3_DCTL_LPM_ERRATA
  usb: dwc3: Fix default lpm_nyet_threshold value
  usb: dwc3: debug: Print GET_STATUS(device) tracepoint
  usb: dwc3: Do core validation early on probe
  usb: dwc3: gadget: Set lpm_capable
  usb: gadget: atmel: tie wake lock to running clock
  usb: gadget: atmel: support USB suspend
  usb: gadget: atmel_usba_udc: simplify setting of interrupt-enabled mask
  dwc2: gadget: Fix completed transfer size calculation in DDMA
  usb: dwc2: Set lpm mode parameters depend on HW configuration
  usb: dwc2: Fix channel disable flow
  usb: dwc2: Set actual frame number for completed ISOC transfer
  usb: gadget: do not use __constant_cpu_to_le16
  usb: dwc2: gadget: Increase descriptors count for ISOC's
  usb: introduce usb_ep_type_string() function
  usb: dwc3: move synchronize_irq() out of the spinlock protected block
  usb: dwc3: Free resource immediately after use
  usb: dwc3: of-simple: Convert to bulk clk API
  usb: dwc2: Delayed status support
  usb: gadget: udc: lpc32xx: rework interrupt handling
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Felipe writes:

USB: changes for v5.2 merge window

With a total of 50 non-merge commits, this is not a large pull
request. Most of the changes are, again, in dwc2 (37%) and dwc3 (32%)
with the rest of it scattered among other UDCs, function drivers and
device-tree bindings.

No really big feature this time around apart from support to Amlogic
being added to both dwc3 and dwc2 drivers.

* tag 'usb-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb: (50 commits)
  usb: dwc3: Rename DWC3_DCTL_LPM_ERRATA
  usb: dwc3: Fix default lpm_nyet_threshold value
  usb: dwc3: debug: Print GET_STATUS(device) tracepoint
  usb: dwc3: Do core validation early on probe
  usb: dwc3: gadget: Set lpm_capable
  usb: gadget: atmel: tie wake lock to running clock
  usb: gadget: atmel: support USB suspend
  usb: gadget: atmel_usba_udc: simplify setting of interrupt-enabled mask
  dwc2: gadget: Fix completed transfer size calculation in DDMA
  usb: dwc2: Set lpm mode parameters depend on HW configuration
  usb: dwc2: Fix channel disable flow
  usb: dwc2: Set actual frame number for completed ISOC transfer
  usb: gadget: do not use __constant_cpu_to_le16
  usb: dwc2: gadget: Increase descriptors count for ISOC's
  usb: introduce usb_ep_type_string() function
  usb: dwc3: move synchronize_irq() out of the spinlock protected block
  usb: dwc3: Free resource immediately after use
  usb: dwc3: of-simple: Convert to bulk clk API
  usb: dwc2: Delayed status support
  usb: gadget: udc: lpc32xx: rework interrupt handling
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Export usb_wakeup_enabled_descendants()</title>
<updated>2019-05-03T06:13:47+00:00</updated>
<author>
<name>Douglas Anderson</name>
<email>dianders@chromium.org</email>
</author>
<published>2019-04-18T00:13:53+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7a6127e39a16c97b505f13352238567fdc3f79a2'/>
<id>7a6127e39a16c97b505f13352238567fdc3f79a2</id>
<content type='text'>
In (e583d9d USB: global suspend and remote wakeup don't mix) we
introduced wakeup_enabled_descendants() as a static function.  We'd
like to use this function in USB controller drivers to know if we
should keep the controller on during suspend time, since doing so has
a power impact.

Signed-off-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Signed-off-by: Felipe Balbi &lt;felipe.balbi@linux.intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In (e583d9d USB: global suspend and remote wakeup don't mix) we
introduced wakeup_enabled_descendants() as a static function.  We'd
like to use this function in USB controller drivers to know if we
should keep the controller on during suspend time, since doing so has
a power impact.

Signed-off-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Signed-off-by: Felipe Balbi &lt;felipe.balbi@linux.intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: core: Don't unbind interfaces following device reset failure</title>
<updated>2019-04-17T12:46:58+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2019-04-16T14:50:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=381419fa720060ba48b7bbc483be787d5b1dca6f'/>
<id>381419fa720060ba48b7bbc483be787d5b1dca6f</id>
<content type='text'>
The SCSI core does not like to have devices or hosts unregistered
while error recovery is in progress.  Trying to do so can lead to
self-deadlock: Part of the removal code tries to obtain a lock already
held by the error handler.

This can cause problems for the usb-storage and uas drivers, because
their error handler routines perform a USB reset, and if the reset
fails then the USB core automatically goes on to unbind all drivers
from the device's interfaces -- all while still in the context of the
SCSI error handler.

As it turns out, practically all the scenarios leading to a USB reset
failure end up causing a device disconnect (the main error pathway in
usb_reset_and_verify_device(), at the end of the routine, calls
hub_port_logical_disconnect() before returning).  As a result, the
hub_wq thread will soon become aware of the problem and will unbind
all the device's drivers in its own context, not in the
error-handler's context.

This means that usb_reset_device() does not need to call
usb_unbind_and_rebind_marked_interfaces() in cases where
usb_reset_and_verify_device() has returned an error, because hub_wq
will take care of everything anyway.

This particular problem was observed in somewhat artificial
circumstances, by using usbfs to tell a hub to power-down a port
connected to a USB-3 mass storage device using the UAS protocol.  With
the port turned off, the currently executing command timed out and the
error handler started running.  The USB reset naturally failed,
because the hub port was off, and the error handler deadlocked as
described above.  Not carrying out the call to
usb_unbind_and_rebind_marked_interfaces() fixes this issue.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Kento Kobayashi &lt;Kento.A.Kobayashi@sony.com&gt;
Tested-by: Kento Kobayashi &lt;Kento.A.Kobayashi@sony.com&gt;
CC: Bart Van Assche &lt;bvanassche@acm.org&gt;
CC: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
CC: Jacky Cao &lt;Jacky.Cao@sony.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The SCSI core does not like to have devices or hosts unregistered
while error recovery is in progress.  Trying to do so can lead to
self-deadlock: Part of the removal code tries to obtain a lock already
held by the error handler.

This can cause problems for the usb-storage and uas drivers, because
their error handler routines perform a USB reset, and if the reset
fails then the USB core automatically goes on to unbind all drivers
from the device's interfaces -- all while still in the context of the
SCSI error handler.

As it turns out, practically all the scenarios leading to a USB reset
failure end up causing a device disconnect (the main error pathway in
usb_reset_and_verify_device(), at the end of the routine, calls
hub_port_logical_disconnect() before returning).  As a result, the
hub_wq thread will soon become aware of the problem and will unbind
all the device's drivers in its own context, not in the
error-handler's context.

This means that usb_reset_device() does not need to call
usb_unbind_and_rebind_marked_interfaces() in cases where
usb_reset_and_verify_device() has returned an error, because hub_wq
will take care of everything anyway.

This particular problem was observed in somewhat artificial
circumstances, by using usbfs to tell a hub to power-down a port
connected to a USB-3 mass storage device using the UAS protocol.  With
the port turned off, the currently executing command timed out and the
error handler started running.  The USB reset naturally failed,
because the hub port was off, and the error handler deadlocked as
described above.  Not carrying out the call to
usb_unbind_and_rebind_marked_interfaces() fixes this issue.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-by: Kento Kobayashi &lt;Kento.A.Kobayashi@sony.com&gt;
Tested-by: Kento Kobayashi &lt;Kento.A.Kobayashi@sony.com&gt;
CC: Bart Van Assche &lt;bvanassche@acm.org&gt;
CC: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
CC: Jacky Cao &lt;Jacky.Cao@sony.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: hub: Remove returned value 'status' since never used</title>
<updated>2019-04-16T10:20:14+00:00</updated>
<author>
<name>Mathieu Malaterre</name>
<email>malat@debian.org</email>
</author>
<published>2019-03-27T19:40:34+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3bee346bd7f36da44890a1de69a389b128617c5a'/>
<id>3bee346bd7f36da44890a1de69a389b128617c5a</id>
<content type='text'>
The returned value in status has never been used since
commit 4296c70a5ec3 ("USB/xHCI: Enable USB 3.0 hub remote wakeup.")
So remove 'status' completely.

Remove warning (W=1):

  drivers/usb/core/hub.c:3671:8: warning: variable 'status' set but not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre &lt;malat@debian.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The returned value in status has never been used since
commit 4296c70a5ec3 ("USB/xHCI: Enable USB 3.0 hub remote wakeup.")
So remove 'status' completely.

Remove warning (W=1):

  drivers/usb/core/hub.c:3671:8: warning: variable 'status' set but not used [-Wunused-but-set-variable]

Signed-off-by: Mathieu Malaterre &lt;malat@debian.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: handle warm-reset port requests on hub resume</title>
<updated>2019-02-08T09:21:22+00:00</updated>
<author>
<name>Jan-Marek Glogowski</name>
<email>glogow@fbihome.de</email>
</author>
<published>2019-02-01T12:52:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4fdc1790e6a9ef22399c6bc6e63b80f4609f3b7e'/>
<id>4fdc1790e6a9ef22399c6bc6e63b80f4609f3b7e</id>
<content type='text'>
On plug-in of my USB-C device, its USB_SS_PORT_LS_SS_INACTIVE
link state bit is set. Greping all the kernel for this bit shows
that the port status requests a warm-reset this way.

This just happens, if its the only device on the root hub, the hub
therefore resumes and the HCDs status_urb isn't yet available.
If a warm-reset request is detected, this sets the hubs event_bits,
which will prevent any auto-suspend and allows the hubs workqueue
to warm-reset the port later in port_event.

Signed-off-by: Jan-Marek Glogowski &lt;glogow@fbihome.de&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
On plug-in of my USB-C device, its USB_SS_PORT_LS_SS_INACTIVE
link state bit is set. Greping all the kernel for this bit shows
that the port status requests a warm-reset this way.

This just happens, if its the only device on the root hub, the hub
therefore resumes and the HCDs status_urb isn't yet available.
If a warm-reset request is detected, this sets the hubs event_bits,
which will prevent any auto-suspend and allows the hubs workqueue
to warm-reset the port later in port_event.

Signed-off-by: Jan-Marek Glogowski &lt;glogow@fbihome.de&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Consolidate LPM checks to avoid enabling LPM twice</title>
<updated>2019-01-18T09:02:56+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2019-01-11T19:54:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d7a6c0ce8d26412903c7981503bad9e1cc7c45d2'/>
<id>d7a6c0ce8d26412903c7981503bad9e1cc7c45d2</id>
<content type='text'>
USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working
after S3:
[ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin
[ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110)

After some experiments, I found that disabling LPM can workaround the
issue.

On some platforms, the USB power is cut during S3, so the driver uses
reset-resume to resume the device. During port resume, LPM gets enabled
twice, by usb_reset_and_verify_device() and usb_port_resume().

Consolidate all checks into new LPM helpers to make sure LPM only gets
enabled once.

Fixes: de68bab4fa96 ("usb: Don't enable USB 2.0 Link PM by default.”)
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt; # after much soaking
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working
after S3:
[ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin
[ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110)

After some experiments, I found that disabling LPM can workaround the
issue.

On some platforms, the USB power is cut during S3, so the driver uses
reset-resume to resume the device. During port resume, LPM gets enabled
twice, by usb_reset_and_verify_device() and usb_port_resume().

Consolidate all checks into new LPM helpers to make sure LPM only gets
enabled once.

Fixes: de68bab4fa96 ("usb: Don't enable USB 2.0 Link PM by default.”)
Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt; # after much soaking
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Add new USB LPM helpers</title>
<updated>2019-01-18T09:02:56+00:00</updated>
<author>
<name>Kai-Heng Feng</name>
<email>kai.heng.feng@canonical.com</email>
</author>
<published>2019-01-11T19:54:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7529b2574a7aaf902f1f8159fbc2a7caa74be559'/>
<id>7529b2574a7aaf902f1f8159fbc2a7caa74be559</id>
<content type='text'>
Use new helpers to make LPM enabling/disabling more clear.

This is a preparation to subsequent patch.

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt; # after much soaking
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Use new helpers to make LPM enabling/disabling more clear.

This is a preparation to subsequent patch.

Signed-off-by: Kai-Heng Feng &lt;kai.heng.feng@canonical.com&gt;
Cc: stable &lt;stable@vger.kernel.org&gt; # after much soaking
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: hub: add retry routine after intr URB submit error</title>
<updated>2019-01-18T08:58:04+00:00</updated>
<author>
<name>Nicolas Saenz Julienne</name>
<email>nsaenzjulienne@suse.de</email>
</author>
<published>2019-01-08T15:45:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8eb58994dd96da7055721c68e46b732febe671ae'/>
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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 &lt;nsaenzjulienne@suse.de&gt;
Reviewed-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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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 &lt;nsaenzjulienne@suse.de&gt;
Reviewed-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
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