[media] uvcvideo: Don't skip erroneous payloads

Instead of skipping the payload completely, which would make the
resulting image corrupted anyway, store the payload normally and mark
the buffer as erroneous. If the no_drop module parameter is set to 1 the
buffer will then be passed to userspace, and tt will then be up to the
application to decide what to do with the buffer.
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/video/uvc/uvc_video.c

@@ -409,13 +409,6 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
 	if (len < 2 || data[0] < 2 || data[0] > len)
 		return -EINVAL;
 
-	/* Skip payloads marked with the error bit ("error frames"). */
-	if (data[1] & UVC_STREAM_ERR) {
-		uvc_trace(UVC_TRACE_FRAME, "Dropping payload (error bit "
-			  "set).\n");
-		return -ENODATA;
-	}
-
 	fid = data[1] & UVC_STREAM_FID;
 
 	/* Increase the sequence number regardless of any buffer states, so
@@ -432,6 +425,13 @@ static int uvc_video_decode_start(struct uvc_streaming *stream,
 		return -ENODATA;
 	}
 
+	/* Mark the buffer as bad if the error bit is set. */
+	if (data[1] & UVC_STREAM_ERR) {
+		uvc_trace(UVC_TRACE_FRAME, "Marking buffer as bad (error bit "
+			  "set).\n");
+		buf->error = 1;
+	}
+
 	/* Synchronize to the input stream by waiting for the FID bit to be
 	 * toggled when the the buffer state is not UVC_BUF_STATE_ACTIVE.
 	 * stream->last_fid is initialized to -1, so the first isochronous