Hi Conrad,
On Monday 22 October 2007, Conrad Beckert wrote:
> Hi Laurent, Hi Simon,
>
> ... I'm the poor guy who has the 064e:a101 Suyin cam troubles :-)
>
> > I'm the maintainer of linphone (video chat tool), and I use uvcvideo
> > driver without major problems every day,
>
> It'd be interessting which device and on what distribution you have.
>
> >I doubt this is a bug in your code. In this context -EPROTO is a low-level
> > USB error generated by the USB stack. It usually indicates faulty devices
> > or cables. What webcams do your complaining users use ?
>
> I have an Acer Travelmate 5720 with the camera built in. So loose USB
> cables aren't an option :-) USB works fine with my scanner, my Philips
> cam, sticks, whatever. It might be worth noticing that the camera is
> internally connected to the USB.
Could you please post the USB descriptors ('lsusb -v' with usbutils 0.72 or
newer) ? Thanks.
> Besides of that camera does work on Linux! I can grab images directly
> with ffmpeg and everything is well.
>
> And I might swear that I've seen the cam working on Linux and Linphone
> on my Notebook. But as I have had sound woes as well, I reinstalled,
> upgraded... and now the images are gone (and the sound partially works)
> but I can't reproduce when this happened.
>
> I meanwhile reinstalled the Windows version of Linphone (after having
> Windows Vista totally off for a while and reinstalled) - and it does not
> work eiher. Linphone-wx crashes when video is on. Other Windows camera
> programs do work though.
Weird, but I don't know if that's related to the Linux issue you reported.
> My suspicion in this case: Something does not set some initial values in
> the driver correctly. ffmpeg does - linphone (or whatever it uses to
> grab the images from the cam) doesn't. No idea where this happens- in
> the app or in the driver...
That's possible but quite unlikely. The driver should initialise the webcam
properly.
There might be a timing issue though. Maybe linphone submits requests so fast
that the camera crashes at some point. Could you raise the trace level
('modprobe uvcvideo trace=255' or 'echo 255
> /sys/modules/uvcvideo/parameters/trace'), start linphone and post the
related portion of the kernel log ('dmesg') ?
> It could well be a different video mode (did I hear somewhere that the
> cam is YUV only? - whatever this means for linphone) - probably the only
> one of the many modes that causes troubles.
The driver will return an error if linphone tries to select an unsupported
format without even bothering the webcam.
Best regards,
Laurent Pinchart
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