Hi Laurent, Apologies for takig so long to get back to you. > I assume that the error message is caused by a race between disconnection and > URB handling. When the device is disconnected I believe the USB core will > cancel all in-progress URBs (I'm not very familiar with that part of the USB > core anymore, so please don't consider this or any further related statement > as true without double-checking), resulting in the URB completion handler > being called with an error status. The completion handler should then avoid > resubmitting the URB. However, if the completion handler is in progress when > the device is disconnected, it won't notice that the device got disconnected, > and will try to resubmit the URB. > > I'm not sure to see how this patch will fix the problem. If the URB completion > handler is in progress when the device is being disconnected, won't it call > usb_submit_urb() regardless of whether you call usb_kill_urb() in the > disconnect handler, resulting in an error message being printed ? You're completely right - I misunderstood the flow of the function. Fixing this would require a different approach and would be more invasive. Given that this does not cause anything more annoying than some log messages, I will leave it for now. Regards, Daniel > >> --- >> drivers/media/usb/uvc/uvc_driver.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/media/usb/uvc/uvc_driver.c >> b/drivers/media/usb/uvc/uvc_driver.c index 2390592f78e0..647e3d8a1256 >> 100644 >> --- a/drivers/media/usb/uvc/uvc_driver.c >> +++ b/drivers/media/usb/uvc/uvc_driver.c >> @@ -1877,6 +1877,8 @@ static void uvc_unregister_video(struct uvc_device >> *dev) if (!video_is_registered(&stream->vdev)) >> continue; >> >> + uvc_video_enable(stream, 0); >> + >> video_unregister_device(&stream->vdev); >> >> uvc_debugfs_cleanup_stream(stream); > > -- > Regards, > > Laurent Pinchart
