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| /openbmc/linux/drivers/hid/usbhid/ |
| H A D | hid-core.c | diff 8f507ef522d55a6e2f9e11a1c1163a92756da044 Tue Sep 02 10:39:15 CDT 2014 Alan Stern <stern@rowland.harvard.edu> HID: usbhid: improve handling of Clear-Halt and reset
This patch changes the way usbhid carries out Clear-Halt and reset.
Currently, after a Clear-Halt on the interrupt-IN endpoint, the driver
immediately restarts the interrupt URB, even if the Clear-Halt failed.
This doesn't work out well when the reason for the failure was that
the device was disconnected (when a low- or full-speed device is
connected through a hub to an EHCI controller, transfer errors caused
by disconnection are reported as stalls by the hub). Instead now the
driver will attempt a reset after a failed Clear-Halt.
The way resets are carried out is also changed. Now the driver will
call usb_queue_reset_device() instead of calling usb_reset_device()
directly. This avoids a deadlock that would arise when a device is
unplugged: The hid_reset() routine runs as a workqueue item, a reset
attempt after the device has been unplugged will fail, failure will
cause usbhid to be unbound, and the disconnect routine will try to do
cancel_work_sync(). The usb_queue_reset_device() implementation is
carefully written to handle scenarios like this one properly.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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