On Tue, 2014-09-02 at 11:39 -0400, Alan Stern wrote:
> 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.
Please disregard my first analysis, I missed a check of the open
counter.
Regards
Oliver
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