V4L/DVB (9031): uvcvideo: Fix incomplete frame drop when switching to a variable size format.

When streaming in a fixed size format the driver sets a flag in the uvc_queue
structure to drop incomplete incoming frames. The flag wasn't cleared when
switching to a variable size format, which resulted in a broken
'MJPEG after YUV'.
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_v4l2.c

@@ -842,10 +842,6 @@ static int uvc_v4l2_do_ioctl(struct inode *inode, struct file *file,
 		if (ret < 0)
 			return ret;
 
-		if (!(video->streaming->cur_format->flags &
-		    UVC_FMT_FLAG_COMPRESSED))
-			video->queue.flags |= UVC_QUEUE_DROP_INCOMPLETE;
-
 		rb->count = ret;
 		ret = 0;
 		break;

drivers/media/video/uvc/uvc_video.c

@@ -971,6 +971,11 @@ int uvc_video_enable(struct uvc_video_device *video, int enable)
 		return 0;
 	}
 
+	if (video->streaming->cur_format->flags & UVC_FMT_FLAG_COMPRESSED)
+		video->queue.flags &= ~UVC_QUEUE_DROP_INCOMPLETE;
+	else
+		video->queue.flags |= UVC_QUEUE_DROP_INCOMPLETE;
+
 	if ((ret = uvc_queue_enable(&video->queue, 1)) < 0)
 		return ret;