2017-12-21 Mauro Carvalho Chehab <mchehab@xxxxxxxxxxxxxxx>:
> Em Mon, 11 Dec 2017 16:27:36 -0200
> Gustavo Padovan <gustavo@xxxxxxxxxxx> escreveu:
>
> > From: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
> >
> > Explicit synchronization benefits a lot from ordered queues, they fit
> > better in a pipeline with DRM for example so create a opt-in way for
> > drivers notify videobuf2 that the queue is unordered.
> >
> > Drivers don't need implement it if the queue is ordered.
> >
> > Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
> > ---
> > include/media/videobuf2-core.h | 5 +++++
> > 1 file changed, 5 insertions(+)
> >
> > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
> > index ef9b64398c8c..eddb38a2a2f3 100644
> > --- a/include/media/videobuf2-core.h
> > +++ b/include/media/videobuf2-core.h
> > @@ -368,6 +368,9 @@ struct vb2_buffer {
> > * callback by calling vb2_buffer_done() with either
> > * %VB2_BUF_STATE_DONE or %VB2_BUF_STATE_ERROR; may use
> > * vb2_wait_for_all_buffers() function
> > + * @is_unordered: tell if the queue format is unordered. The default is
> > + * assumed to be ordered and this function only needs to
> > + * be implemented for unordered queues.
> > * @buf_queue: passes buffer vb to the driver; driver may start
> > * hardware operation on this buffer; driver should give
> > * the buffer back by calling vb2_buffer_done() function;
> > @@ -391,6 +394,7 @@ struct vb2_ops {
> >
> > int (*start_streaming)(struct vb2_queue *q, unsigned int count);
> > void (*stop_streaming)(struct vb2_queue *q);
> > + int (*is_unordered)(struct vb2_queue *q);
> >
> > void (*buf_queue)(struct vb2_buffer *vb);
> > };
> > @@ -564,6 +568,7 @@ struct vb2_queue {
> > u32 cnt_wait_finish;
> > u32 cnt_start_streaming;
> > u32 cnt_stop_streaming;
> > + u32 cnt_is_unordered;
>
> If I understand, this is just a bit, right?
>
> if so, better to declare it as:
>
> u32 cnt_is_unordered : 1;
no, is_unordered() is a vb2 callback to ask drivers if their current
queue is not ordered and cnt_is_unordered is the counter of how many
times this callback was called. This happens for all vb2 callbacks, see
the other counters above, so I decided to add one for is_unordered() as
well.
Gustavo
