From c16218402a000bb25c1277c43ae98c11bcb59bd1 Mon Sep 17 00:00:00 2001 From: Philipp Zabel Date: Mon, 4 May 2015 07:51:06 -0300 Subject: [PATCH] [media] videobuf2: return -EPIPE from DQBUF after the last buffer If the last buffer was dequeued from a capture queue, let poll return immediately and let DQBUF return -EPIPE to signal there will no more buffers to dequeue until STREAMOFF. The driver signals the last buffer by setting the V4L2_BUF_FLAG_LAST. To reenable dequeuing on the capture queue, the driver must explicitly call vb2_clear_last_buffer_queued. The last buffer queued flag is cleared automatically during STREAMOFF. Signed-off-by: Philipp Zabel Acked-by: Hans Verkuil Signed-off-by: Kamil Debski Signed-off-by: Mauro Carvalho Chehab --- drivers/media/v4l2-core/v4l2-mem2mem.c | 10 +++++++++- drivers/media/v4l2-core/videobuf2-core.c | 19 ++++++++++++++++++- include/media/videobuf2-core.h | 13 +++++++++++++ 3 files changed, 40 insertions(+), 2 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-mem2mem.c b/drivers/media/v4l2-core/v4l2-mem2mem.c index 73824a5..cbef15c 100644 --- a/drivers/media/v4l2-core/v4l2-mem2mem.c +++ b/drivers/media/v4l2-core/v4l2-mem2mem.c @@ -564,8 +564,16 @@ unsigned int v4l2_m2m_poll(struct file *file, struct v4l2_m2m_ctx *m2m_ctx, if (list_empty(&src_q->done_list)) poll_wait(file, &src_q->done_wq, wait); - if (list_empty(&dst_q->done_list)) + if (list_empty(&dst_q->done_list)) { + /* + * If the last buffer was dequeued from the capture queue, + * return immediately. DQBUF will return -EPIPE. + */ + if (dst_q->last_buffer_dequeued) + return rc | POLLIN | POLLRDNORM; + poll_wait(file, &dst_q->done_wq, wait); + } if (m2m_ctx->m2m_dev->m2m_ops->lock) m2m_ctx->m2m_dev->m2m_ops->lock(m2m_ctx->priv); diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 20cdbc0..552d7e1 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -1943,6 +1943,11 @@ static int __vb2_wait_for_done_vb(struct vb2_queue *q, int nonblocking) return -EIO; } + if (q->last_buffer_dequeued) { + dprintk(3, "last buffer dequeued already, will not wait for buffers\n"); + return -EPIPE; + } + if (!list_empty(&q->done_list)) { /* * Found a buffer that we were waiting for. @@ -2098,6 +2103,9 @@ static int vb2_internal_dqbuf(struct vb2_queue *q, struct v4l2_buffer *b, bool n /* Remove from videobuf queue */ list_del(&vb->queued_entry); q->queued_count--; + if (!V4L2_TYPE_IS_OUTPUT(q->type) && + vb->v4l2_buf.flags & V4L2_BUF_FLAG_LAST) + q->last_buffer_dequeued = true; /* go back to dequeued state */ __vb2_dqbuf(vb); @@ -2311,6 +2319,7 @@ static int vb2_internal_streamoff(struct vb2_queue *q, enum v4l2_buf_type type) */ __vb2_queue_cancel(q); q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type); + q->last_buffer_dequeued = false; dprintk(3, "successful\n"); return 0; @@ -2653,8 +2662,16 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait) if (V4L2_TYPE_IS_OUTPUT(q->type) && q->queued_count < q->num_buffers) return res | POLLOUT | POLLWRNORM; - if (list_empty(&q->done_list)) + if (list_empty(&q->done_list)) { + /* + * If the last buffer was dequeued from a capture queue, + * return immediately. DQBUF will return -EPIPE. + */ + if (q->last_buffer_dequeued) + return res | POLLIN | POLLRDNORM; + poll_wait(file, &q->done_wq, wait); + } /* * Take first buffer available for dequeuing. diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index a5790fd..22a44c2 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -381,6 +381,9 @@ struct v4l2_fh; * @waiting_for_buffers: used in poll() to check if vb2 is still waiting for * buffers. Only set for capture queues if qbuf has not yet been * called since poll() needs to return POLLERR in that situation. + * @last_buffer_dequeued: used in poll() and DQBUF to immediately return if the + * last decoded buffer was already dequeued. Set for capture queues + * when a buffer with the V4L2_BUF_FLAG_LAST is dequeued. * @fileio: file io emulator internal data, used only if emulator is active * @threadio: thread io internal data, used only if thread is active */ @@ -423,6 +426,7 @@ struct vb2_queue { unsigned int start_streaming_called:1; unsigned int error:1; unsigned int waiting_for_buffers:1; + unsigned int last_buffer_dequeued:1; struct vb2_fileio_data *fileio; struct vb2_threadio_data *threadio; @@ -603,6 +607,15 @@ static inline bool vb2_start_streaming_called(struct vb2_queue *q) return q->start_streaming_called; } +/** + * vb2_clear_last_buffer_dequeued() - clear last buffer dequeued flag of queue + * @q: videobuf queue + */ +static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q) +{ + q->last_buffer_dequeued = false; +} + /* * The following functions are not part of the vb2 core API, but are simple * helper functions that you can use in your struct v4l2_file_operations, -- 2.7.4