v4l1 (linux/videodev.h) and libv4l

Hans de Goede hdegoede at redhat.com
Wed Feb 9 13:19:06 UTC 2011


On 02/09/2011 09:11 AM, Kevin Kofler wrote:
> Hi,
> several of the build failures in Rawhide are due to the removal of v4l1 from
> the kernel, which manifests itself as a missing<linux/videodev.h>  header.
> (I think there was a thread about that on this list already, but I can't
> find it now.)
> My questions:
> * Couldn't v4l1-only apps be made to work with minimal porting effort
> through libv4l's libv4l1compat, without v4l1 support in the kernel?

Yes, libv4l's libv4l1compat was extended recently to no longer rely on
the in kernel compat at all.

> * libv4l's libv4l1compat itself also fails to build due to a missing
> <linux/videodev.h>. It obviously needs the #defines there to emulate the
> API. Should libv4l ship that header now?

That header should be integrated into the libv4l1 header, this is on my
to do list.

> * It's quite embarassing to have libv4l be one of the packages failing to
> build due to a kernel v4l change. Why wasn't this change coordinated with
> libv4l?

It was (I'm the libv4l author / maintainer and knew this was coming for
months) yet when it actually happened it still managed to catch me by
surprise :)

I plan to have a fixed libv4l package out soon. All apps which break because
of this should already be using libv4l1 (purely relying on kernel v4l1 compat
has not been a good idea for ages), so they should already be including
libv4l1.h in all the right places, all that should be needed once libv4l is
fixed is no longer also including <linux/videodev.h>.



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