[media] uvcvideo: Set alternate setting 0 on resume if the bus has be…

…en reset

If the bus has been reset on resume, set the alternate setting to 0.
This should be the default value, but some devices crash or otherwise
misbehave if they don't receive a SET_INTERFACE request before any other
video control request.

Microdia's 0c45:6437 camera has been found to require this change or it
will stop sending video data after resume.

uvc_video.c]

Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_driver.c

@@ -1961,7 +1961,7 @@ static int __uvc_resume(struct usb_interface *intf, int reset)
 
 	list_for_each_entry(stream, &dev->streams, list) {
 		if (stream->intf == intf)
-			return uvc_video_resume(stream);
+			return uvc_video_resume(stream, reset);
 	}
 
 	uvc_trace(UVC_TRACE_SUSPEND, "Resume: video streaming USB interface "

drivers/media/video/uvc/uvc_video.c

@@ -1104,10 +1104,18 @@ int uvc_video_suspend(struct uvc_streaming *stream)
  * buffers, making sure userspace applications are notified of the problem
  * instead of waiting forever.
  */
-int uvc_video_resume(struct uvc_streaming *stream)
+int uvc_video_resume(struct uvc_streaming *stream, int reset)
 {
 	int ret;
 
+	/* If the bus has been reset on resume, set the alternate setting to 0.
+	 * This should be the default value, but some devices crash or otherwise
+	 * misbehave if they don't receive a SET_INTERFACE request before any
+	 * other video control request.
+	 */
+	if (reset)
+		usb_set_interface(stream->dev->udev, stream->intfnum, 0);
+
 	stream->frozen = 0;
 
 	ret = uvc_commit_video(stream, &stream->ctrl);

drivers/media/video/uvc/uvcvideo.h

@@ -638,7 +638,7 @@ extern void uvc_mc_cleanup_entity(struct uvc_entity *entity);
 /* Video */
 extern int uvc_video_init(struct uvc_streaming *stream);
 extern int uvc_video_suspend(struct uvc_streaming *stream);
-extern int uvc_video_resume(struct uvc_streaming *stream);
+extern int uvc_video_resume(struct uvc_streaming *stream, int reset);
 extern int uvc_video_enable(struct uvc_streaming *stream, int enable);
 extern int uvc_probe_video(struct uvc_streaming *stream,
 		struct uvc_streaming_control *probe);