[Linux-uvc-devel] Acer Webcam/ linux fedora 7

Laurent Pinchart laurent.pinchart at skynet.be
Tue Aug 21 21:17:40 CEST 2007

Hi Francisco,

On Monday 20 August 2007, Francisco Vera wrote:
> On Saturday 18 August 2007 06:46, Mickael Drean wrote:
> > I've tested to launch luvcvideo on GNOME instead of KDE and I get an
> > error message :
> > luvcview version 0.2.1
> > Video driver: x11
> > A window manager is available
> > video /dev/video0
> > Unable to set format: 16.
> >  Init v4L2 failed !! exit fatal
> I have similar problems but with the message: Unable to set format: 5

That's indeed a different issue.

> I know these are different problems but luvcview and the uvc driver were
> working ok and after an upgrade the problems begun. My camera is a logitech
> fusion.
> The problem appears to be an initialization problem in luvcview because
> luvcview work as expected when v4l-info is run first.
> Now luvcview is packaged for debian, so in debian unstable all that is
> needed to get an UVC camera running is:
> apt-get install luvcview
> apt-get install module-assistant
> apt-get install v4l-conf
> m-a a-i linux-uvc
> m-a is a nickname for module-assistant
> v4l-conf is needed for v4l-info
> then run v4l-info and luvcview

I might be wrong, but I *think* this isn't luvcview's fault. Could you check 
the kernel log after running luvcview (and getting the 'Unable to set format: 
5' message, thus without running v4l-conf first) ? If you get a 'Failed to 
query (1) UVC control 1 (unit 0)' message, you ran into a known 
hardware/firmware Logitech bug. There's no way to fix it: the problem is due 
to subtle timing issues, so running another software first, plugging the 
webcam into another port or throttling your CPU might make thinks better or 
worse. That's completely random.

Best regards,

Laurent Pinchart

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