On Fri, 2013-12-20 at 14:07 +0100, Bjørn Mork wrote:
> commit 73e06865ead1 ("USB: cdc-wdm: support back-to-back
> USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications") implemented
> queued response handling. This added a new requirement: The read
> urb must be resubmitted every time we clear the WDM_READ flag if
> the response counter indicates that the device is waiting for a
> read.
>
> Fix by factoring out the code handling the WMD_READ clearing and
> possible urb submission, calling it everywhere we clear the flag.
>
> Without this fix, the driver ends up in a state where the read urb
> is inactive, but the response counter is positive after a zero
> length read. This prevents the read urb from ever being submitted
> again and the driver appears to be hanging.
>
> Fixes: 73e06865ead1 ("USB: cdc-wdm: support back-to-back
> USB_CDC_NOTIFY_RESPONSE_AVAILABLE notifications")
> Cc: Greg Suarez <gsuarez@xxxxxxxxxxxxxx>
> Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
Acked-by: Oliver Neukum <oliver@xxxxxxxxxx>
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