From 650b95feee353305203724cb2e8b2bc50f6d130a Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Sat, 2 Oct 2010 11:06:05 -0300 Subject: [PATCH] [media] uvcvideo: Generate discontinuous sequence numbers when frames are lost Increase the sequence number of the v4l2_buffer structure regardless of any buffer states, so that discontinuous sequence numbers allow applications to detect lost video frames. Signed-off-by: Laurent Pinchart Signed-off-by: Mauro Carvalho Chehab --- drivers/media/video/uvc/uvc_queue.c | 7 +------ drivers/media/video/uvc/uvc_video.c | 9 +++++++++ drivers/media/video/uvc/uvcvideo.h | 2 +- 3 files changed, 11 insertions(+), 7 deletions(-) diff --git a/drivers/media/video/uvc/uvc_queue.c b/drivers/media/video/uvc/uvc_queue.c index d27a315..ed6d544 100644 --- a/drivers/media/video/uvc/uvc_queue.c +++ b/drivers/media/video/uvc/uvc_queue.c @@ -135,7 +135,6 @@ int uvc_alloc_buffers(struct uvc_video_queue *queue, unsigned int nbuffers, queue->buffer[i].buf.m.offset = i * bufsize; queue->buffer[i].buf.length = buflength; queue->buffer[i].buf.type = queue->type; - queue->buffer[i].buf.sequence = 0; queue->buffer[i].buf.field = V4L2_FIELD_NONE; queue->buffer[i].buf.memory = V4L2_MEMORY_MMAP; queue->buffer[i].buf.flags = 0; @@ -410,8 +409,7 @@ done: * state can be properly initialized before buffers are accessed from the * interrupt handler. * - * Enabling the video queue initializes parameters (such as sequence number, - * sync pattern, ...). If the queue is already enabled, return -EBUSY. + * Enabling the video queue returns -EBUSY if the queue is already enabled. * * Disabling the video queue cancels the queue and removes all buffers from * the main queue. @@ -430,7 +428,6 @@ int uvc_queue_enable(struct uvc_video_queue *queue, int enable) ret = -EBUSY; goto done; } - queue->sequence = 0; queue->flags |= UVC_QUEUE_STREAMING; queue->buf_used = 0; } else { @@ -510,8 +507,6 @@ struct uvc_buffer *uvc_queue_next_buffer(struct uvc_video_queue *queue, nextbuf = NULL; spin_unlock_irqrestore(&queue->irqlock, flags); - buf->buf.sequence = queue->sequence++; - wake_up(&buf->wait); return nextbuf; } diff --git a/drivers/media/video/uvc/uvc_video.c b/drivers/media/video/uvc/uvc_video.c index 5a2022c..5555f01 100644 --- a/drivers/media/video/uvc/uvc_video.c +++ b/drivers/media/video/uvc/uvc_video.c @@ -427,6 +427,12 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, fid = data[1] & UVC_STREAM_FID; + /* Increase the sequence number regardless of any buffer states, so + * that discontinuous sequence numbers always indicate lost frames. + */ + if (stream->last_fid != fid) + stream->sequence++; + /* Store the payload FID bit and return immediately when the buffer is * NULL. */ @@ -460,6 +466,7 @@ static int uvc_video_decode_start(struct uvc_streaming *stream, else ktime_get_real_ts(&ts); + buf->buf.sequence = stream->sequence; buf->buf.timestamp.tv_sec = ts.tv_sec; buf->buf.timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC; @@ -721,6 +728,7 @@ static void uvc_video_encode_bulk(struct urb *urb, struct uvc_streaming *stream, if (buf->buf.bytesused == stream->queue.buf_used) { stream->queue.buf_used = 0; buf->state = UVC_BUF_STATE_READY; + buf->buf.sequence = ++stream->sequence; uvc_queue_next_buffer(&stream->queue, buf); stream->last_fid ^= UVC_STREAM_FID; } @@ -979,6 +987,7 @@ static int uvc_init_video(struct uvc_streaming *stream, gfp_t gfp_flags) unsigned int i; int ret; + stream->sequence = -1; stream->last_fid = -1; stream->bulk.header_size = 0; stream->bulk.skip_payload = 0; diff --git a/drivers/media/video/uvc/uvcvideo.h b/drivers/media/video/uvc/uvcvideo.h index 892e0e5..f890133 100644 --- a/drivers/media/video/uvc/uvcvideo.h +++ b/drivers/media/video/uvc/uvcvideo.h @@ -392,7 +392,6 @@ struct uvc_video_queue { void *mem; unsigned int flags; - __u32 sequence; unsigned int count; unsigned int buf_size; @@ -458,6 +457,7 @@ struct uvc_streaming { dma_addr_t urb_dma[UVC_URBS]; unsigned int urb_size; + __u32 sequence; __u8 last_fid; }; -- 2.7.4