On Mon, 15 Aug 2011, Guennadi Liakhovetski wrote:
> On Mon, 15 Aug 2011, Hans Verkuil wrote:
>
> > On Monday, August 15, 2011 13:28:23 Guennadi Liakhovetski wrote:
> > > Hi Hans
> > >
> > > On Mon, 8 Aug 2011, Hans Verkuil wrote:
[snip]
> > > > but I've changed my mind: I think
> > > > this should use a struct v4l2_format after all.
>
> While switching back, I have to change the struct vb2_ops::queue_setup()
> operation to take a struct v4l2_create_buffers pointer. An earlier version
> of this patch just added one more parameter to .queue_setup(), which is
> easier - changes to videobuf2-core.c are smaller, but it is then
> redundant. We could use the create pointer for both input and output. The
> video plane configuration in frame format is the same as what is
> calculated in .queue_setup(), IIUC. So, we could just let the driver fill
> that one in. This would require then the videobuf2-core.c to parse struct
> v4l2_format to decide which union member we need, depending on the buffer
> type. Do we want this or shall drivers duplicate plane sizes in separate
> .queue_setup() parameters?
Let me explain my question a bit. The current .queue_setup() method is
int (*queue_setup)(struct vb2_queue *q, unsigned int *num_buffers,
unsigned int *num_planes, unsigned int sizes[],
void *alloc_ctxs[]);
To support multiple-size buffers we also have to pass a pointer to struct
v4l2_create_buffers to this function now. We can either do it like this:
int (*queue_setup)(struct vb2_queue *q,
struct v4l2_create_buffers *create,
unsigned int *num_buffers,
unsigned int *num_planes, unsigned int sizes[],
void *alloc_ctxs[]);
and let all drivers fill in respective fields in *create, e.g., either do
create->format.fmt.pix_mp.plane_fmt[i].sizeimage = ...;
create->format.fmt.pix_mp.num_planes = ...;
and also duplicate it in method parameters
*num_planes = create->format.fmt.pix_mp.num_planes;
sizes[i] = create->format.fmt.pix_mp.plane_fmt[i].sizeimage;
or with
create->format.fmt.pix.sizeimage = ...;
for single-plane. Alternatively we make the prototype
int (*queue_setup)(struct vb2_queue *q,
struct v4l2_create_buffers *create,
unsigned int *num_buffers,
void *alloc_ctxs[]);
then drivers only fill in *create, and the videobuf2-core will have to
check create->format.type to decide, which of create->format.fmt.* is
relevant and extract plane sizes from there.
Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
