Which Userland Interface for USB Video Class Driver?

[Hans Petter Selasky]

On Tuesday 23 September 2008, Fritz Katz wrote:
> On Monday, September 22, 2008 5:33 AM, Intron <intron(at)intron(dot)ac> 
wrote:
> > I would write/port a driver for USB video class for FreeBSD's
> > new USB stack (usb2). OpenBSD and NetBSD both has had their
> > own implementations for the device class as some people referred
> > to recently. But which userland interface, bktr(4) or V4L2, should
> > I use for the driver?
>
>   We've only got two choices:
>   -- bktr is dead,
>   -- and V4L2 doesn't exist.
>
>   bktr is a dead end. The Brooktree company no longer exists.
>   Conexant stopped making bktr chips years ago.
>   It only supports analog -- analog is a dead end too.
>
>   Instead, look at Jason Harmening's work on cx88 support:
>  
> http://lists.freebsd.org/pipermail/freebsd-multimedia/2008-September/009116
>.html
>
>   ... that's the future.
>
>   V4L2 has a well defined interface, and numerous applications
>   already support it. It's not tied to any particular hardware,
>   company, or chip so it's not going to die like bktr did.
>
>   IMHO, V4L2 should be the future for BSDs as well.
>
>   Implementing a V4L2-IOCTL interface would be a moderately difficult
>   but very rewarding project.

Hi,

Maybe you will find the following file useful:

http://perforce.freebsd.org/fileLogView.cgi?FSPC=//depot/projects/usb/src/sys/sys/videodev.h

Regarding porting, there is not much you need to do. Simply make sure that you 
handle the IOCTLs directly in the video driver.

--HPS

>
> > I have noticed that Julian has done some work for V4L2:
>
> http://perforce.freebsd.org/depotTreeBrowser.cgi?FSPC=//depot/user/julian/j
>ulian%5fv4l/sys/dev/video/framework&HIDEDEL=NO
>
> > But I wonder how soon Julian's code can be committed into
> > the main source tree. I wouldn't see the driver sleeps outside
> > the main source tree.
>
> Looks like no activity in that tree since 2006/08/24 -- I don't see it
> being committed anytime soon.
>
> I've started a project to bring V4L2 to BSDs here:
>   http://video4bsd.sourceforge.net/
>
> Cheers,
> -- Fritz Katz.
>
>
>
>
>
> _______________________________________________
> freebsd-multimedia at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-multimedia
> To unsubscribe, send any mail to
> "freebsd-multimedia-unsubscribe at freebsd.org"