path: root/drivers/media
diff options
authorHans Verkuil <hans.verkuil@cisco.com>2014-09-20 16:16:35 -0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-10-09 12:18:42 -0700
commitf5d34b7cae6c6ddddb1797ebc0d0918954544108 (patch)
tree1be3ce71e9e730fe3f8e9f15d38ceca50a40e06a /drivers/media
parentf35407acce23bab3727190a94468362dc8f030a1 (diff)
media: vb2: fix VBI/poll regression
commit 58d75f4b1ce26324b4d809b18f94819843a98731 upstream. The recent conversion of saa7134 to vb2 unconvered a poll() bug that broke the teletext applications alevt and mtt. These applications expect that calling poll() without having called VIDIOC_STREAMON will cause poll() to return POLLERR. That did not happen in vb2. This patch fixes that behavior. It also fixes what should happen when poll() is called when STREAMON is called but no buffers have been queued. In that case poll() will also return POLLERR, but only for capture queues since output queues will always return POLLOUT anyway in that situation. This brings the vb2 behavior in line with the old videobuf behavior. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/media')
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
index e3bdc3be91e1..5e47ba479e53 100644
--- a/drivers/media/v4l2-core/videobuf2-core.c
+++ b/drivers/media/v4l2-core/videobuf2-core.c
@@ -666,6 +666,7 @@ static int __reqbufs(struct vb2_queue *q, struct v4l2_requestbuffers *req)
* to the userspace.
req->count = allocated_buffers;
+ q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
return 0;
@@ -714,6 +715,7 @@ static int __create_bufs(struct vb2_queue *q, struct v4l2_create_buffers *create
memset(q->plane_sizes, 0, sizeof(q->plane_sizes));
memset(q->alloc_ctx, 0, sizeof(q->alloc_ctx));
q->memory = create->memory;
+ q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
num_buffers = min(create->count, VIDEO_MAX_FRAME - q->num_buffers);
@@ -1355,6 +1357,7 @@ int vb2_qbuf(struct vb2_queue *q, struct v4l2_buffer *b)
* dequeued in dqbuf.
list_add_tail(&vb->queued_entry, &q->queued_list);
+ q->waiting_for_buffers = false;
vb->state = VB2_BUF_STATE_QUEUED;
@@ -1724,6 +1727,7 @@ int vb2_streamoff(struct vb2_queue *q, enum v4l2_buf_type type)
* and videobuf, effectively returning control over them to userspace.
+ q->waiting_for_buffers = !V4L2_TYPE_IS_OUTPUT(q->type);
dprintk(3, "Streamoff successful\n");
return 0;
@@ -2009,9 +2013,16 @@ unsigned int vb2_poll(struct vb2_queue *q, struct file *file, poll_table *wait)
- * There is nothing to wait for if no buffers have already been queued.
+ * There is nothing to wait for if the queue isn't streaming.
- if (list_empty(&q->queued_list))
+ if (!vb2_is_streaming(q))
+ return res | POLLERR;
+ /*
+ * For compatibility with vb1: if QBUF hasn't been called yet, then
+ * return POLLERR as well. This only affects capture queues, output
+ * queues will always initialize waiting_for_buffers to false.
+ */
+ if (q->waiting_for_buffers)
return res | POLLERR;
if (list_empty(&q->done_list))