Hi Hans, On Sunday 21 September 2014 11:34:26 Hans Verkuil wrote: > On 09/21/2014 11:30 AM, Laurent Pinchart wrote: > > On Sunday 21 September 2014 11:00:02 Hans Verkuil wrote: > >> On 09/20/2014 09:26 PM, Laurent Pinchart wrote: > >>> On Saturday 20 September 2014 21:16:35 Hans Verkuil wrote: > >>>> From: Hans Verkuil <hans.verkuil@xxxxxxxxx> > >>>> > >>>> 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@xxxxxxxxx> > >>>> --- > >>>> > >>>> drivers/media/v4l2-core/videobuf2-core.c | 17 ++++++++++++++--- > >>>> include/media/videobuf2-core.h | 4 ++++ > >>>> 2 files changed, 18 insertions(+), 3 deletions(-) > >>>> > >>>> diff --git a/drivers/media/v4l2-core/videobuf2-core.c > >>>> b/drivers/media/v4l2-core/videobuf2-core.c index 7e6aff6..a0aa694 > >>>> 100644 > >>>> --- a/drivers/media/v4l2-core/videobuf2-core.c > >>>> +++ b/drivers/media/v4l2-core/videobuf2-core.c > >>>> @@ -977,6 +977,7 @@ 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; > >>>> > >>>> } > >>>> > >>>> @@ -1024,6 +1025,7 @@ 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); > >>> > >>> Wouldn't it be easier to set the flag when creating the queue and in > >>> vb2_internal_streamoff() instead of in __create_bufs and __reqbufs ? > >>> I'll > >>> let you decide. > >> > >> Sorry, I don't follow. 'When creating the queue'? __create_bufs and > >> __reqbufs are the functions that create the queue (i.e. allocate the > >> buffers). > > > > I meant vb2_queue_init. > > That's not an option as it is called only once at probe time. I know :-) > And this flag needs to be set every time you setup the queue for streaming, > when you stop streaming and when you queue a buffer. I was thinking it would be enough to set the flag when stopping the stream, as it would then be set for the next REQBUFS or CREATE_BUFS operation, but that would break if an application calls QBUF - close() - open() - ... Let's proceed with your patch. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
