[media] uvcvideo: Fix frame drop in bulk video stream

When video endpoint is configured as bulk, a ZLP is sent after every
video frames with size as multiple of 512 bytes. This is done so that
host can detect end of transfer and pass data for processing.
Still, frames that are multiple of 16K in size gets dropped. The ZLP
sent by camera is ignored by uvc_video_decode_bulk(). The makes sure
that the ZLP is not part of a video frame before ignoring it. If ZLP
follows a video frame, then it triggers completion callback.

[mchehab@redhat.com: Fix a small CodingStyle issue]
Signed-off-by: Jayakrishnan Memana <jayakrishnan.memana@maxim-ic.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c
index b76b0ac0958f8d2d27a5a7193c623badfac5ee67..39f5c85dd4b4e5c5e5c8a5c00805411a991c276e 100644 (file)
--- a/drivers/media/video/uvc/uvc_video.c
+++ b/drivers/media/video/uvc/uvc_video.c
@@ -1188,7 +1188,11 @@ static void uvc_video_decode_bulk(struct urb *urb, struct uvc_streaming *stream,
        u8 *mem;
        int len, ret;
 
-       if (urb->actual_length == 0)
+       /*
+        * Ignore ZLPs if they're not part of a frame, otherwise process them
+        * to trigger the end of payload detection.
+        */
+       if (urb->actual_length == 0 && stream->bulk.header_size == 0)
                return;
 
        mem = urb->transfer_buffer;