[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 <p.zabel@pengutronix.de>
Acked-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Kamil Debski <k.debski@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
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 @@
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 @@
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 @@
/* 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 @@
*/
__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 @@
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.