[PATCH] cafe_ccic: add support for VIDIOC_ENUM_FRAMESIZES and VIDIOC_ENUM_FRAMEINTERVALS

[Jonathan Corbet]

Dan Williams <dcbw at redhat.com> wrote:

> Newer gstreamer v4l2 plugins require these ioctls to determine supported
> frame sizes and rates.  Unfortunately, the kernel v4l2 bits don't have
> members in 'struct video_device' for these ioctls, so we have to
> override the generic ioctl handler for these two functions.  They report
> only VGA size @ 30fps as being supported for now.

Interesting, I didn't know about that.  I just sent a question off to
Mauro (the V4L2 maintainer) on why those ioctls aren't wired up through
video_ioctl2().  His answer, essentially, is "nobody was using them
yet."

I don't think this patch is destined for the mainline in its current
form.  The right thing to do is to add callbacks for those commands and
support them for all drivers through video_ioctl2().  Shouldn't be that
hard of a thing to do.  Once that's done, the cafe_ccic driver should
really just push those commands down to the sensor layer.  Then you
could actually enumerate the real frame sizes and supported rates and
you would not have to wire assumptions about the supported video formats
into the controller driver.

I'm traveling (again, sigh) next week, but could probably hack something
up the week after if you don't want to spend more time on this.

jon