On Tuesday 05 April 2011 14:52:20 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.
>
> Why??? You do not need all that extra information. Well, we could, of
> course, make a struct with reserved fields... but it seems nice to me to
> have the clarity here - this ioctl() _only_ gives buffer ownership to the
> kernel. No more configuration...
Right now you're correct. In the future we might need extra fields, so we need
a structure with reserved fields.
--
Regards,
Laurent Pinchart
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