On Wednesday, April 06, 2011 18:19:18 Guennadi Liakhovetski wrote:
> On Tue, 5 Apr 2011, Hans Verkuil wrote:
>
> > On Tuesday, April 05, 2011 14:21:03 Laurent Pinchart wrote:
> > > On Friday 01 April 2011 10:13:02 Guennadi Liakhovetski wrote:
>
> [snip]
>
> > > > * I O C T L C O D E S F O R V I D E O D E V I C E S
> > > > *
> > > > @@ -1937,6 +1957,10 @@ struct v4l2_dbg_chip_ident {
> > > > #define VIDIOC_SUBSCRIBE_EVENT _IOW('V', 90, struct
> > > > v4l2_event_subscription) #define VIDIOC_UNSUBSCRIBE_EVENT
> > > > _IOW('V', 91,
> > > > struct v4l2_event_subscription)
> > > >
> > > > +#define VIDIOC_CREATE_BUFS _IOWR('V', 92, struct
> > > > v4l2_create_buffers)
> > > > +#define VIDIOC_DESTROY_BUFS _IOWR('V', 93, struct v4l2_buffer_span)
> > > > +#define VIDIOC_SUBMIT_BUF _IOW('V', 94, int)
> > > > +
> > >
> > > In case we later need to pass other information (such as flags) to
> > > VIDIOC_SUBMIT_BUF, you should use a structure instead of an int.
> >
> > I would just pass struct v4l2_buffer to this ioctl, just like QBUF/DQBUF do.
>
> As I said, I didn't like this very much, because it involves redundant
> data, but if we want to call .buf_prepare() from it, then we need
> v4l2_buffer...
I don't see a problem with this. Applications already *have* the v4l2_buffer
after all. It's not as if they have to fill that structure just for this call.
Furthermore, you need all that data anyway because you need to do the same
checks that vb2_qbuf does.
Regarding DESTROY_BUFS: perhaps we should just skip this for now and wait for
the first use-case. That way we don't need to care about holes. I don't like
artificial restrictions like 'no holes'. If someone has a good use-case for
selectively destroying buffers, then we need to look at this again.
Regards,
Hans
>
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
>
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