Re: [Linux-uvc-devel] [Linphone-developers] 064e:a101 Suyin Corp. Cam in Acer Notebook

[Simon Morlat]

Hi,

Thank you for the advice. I wonder if the problem isn't related to threads, 
since the grabbing process is done within a dedicated thread in linphone. 
Furthermore, the init phase (open, ioctl to setup format and size) is done 
from one thread, while the mmaps, stream-on and QBUF and DQBUF are done by 
another thread.
However the instructions are serialised (the mmap/stream-on/Q/DQ) occurs AFTER 
the init phase.
But I wonder if it cannot confuse the usb stack.
The last complain was from somebody using an "Acer CrystalEye" camera.

Simon

Le Saturday 13 October 2007 12:23:57 Laurent Pinchart, vous avez écrit :
> Hi Simon,
>
> On Friday 12 October 2007, Simon Morlat wrote:
> > Hi,
> >
> > I'm the maintainer of linphone (video chat tool), and I use uvcvideo
> > driver without major problems every day,
>
> Nice to hear :-)
>
> > however I receive many complaints of users having "Protocol error"
> > (EPROT) returned by the VIDEOC_STREAMON ioctl.
>
> Not as nice :-/
>
> > The bug is probably in my code, but if you have any hints about the
> > meaning of this error, you're welcome !
>
> 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 ?
>
> Best regards,
>
> Laurent Pinchart