Re: [Linux-uvc-devel] Test of the driver on GNU/Debian amd64

[Laurent P. <lau...@sk...>]

Hi Olivier,

first of all, thanks for your interest in the project, and thanks for your 
patch. It has been applied to SVN.

> first, I'm happy to see the support of the new Logitech webcams under
> Linux... Even if this is not coming from Logitech itself. (I think it's
> an error from Logitech to not making some opensource drivers for their
> products, like for example Intel started with their ipw2100/2200 wifi
> cards).

I've contacted Logitech a few months ago, and they were very interested in the 
project. Linux is clearly a market they can't ignore anymore, but they 
currently don't have development resources to assign to Linux drivers 
development. They offered their help and are very supportive.

> linux-uvc is revision 3 from svn trunk. One remark: the info on the
> berlios page http://developer.berlios.de/svn/?group_id=5681 is not
> correct for downloading the project. Instead of doing:
>
>   svn checkout svn://svn.berlios.de/linux-uvc/trunk
>
> as described, I have done:
>
>   svn checkout svn://svn.berlios.de/linux-uvc/linux-uvc/trunk
>
> Maybe a small re-organisation of the svn tree will be great ? (to have
> directly trunk instead of linux-uvc/trunk). This will help users to
> download the tree with the berlios instructions.

I created a linux-uvc directory on purpose, as the project is very likely to 
release more software soon (sample SDL V4L2 viewer for instance, or patches 
for software like usbutils, GnomeMeeting or Kopete). I planned to organise 
SVN in way similar to this :

linux-uvc
  linux-uvc		(Kernel driver)
    branches
    tags
    trunk
  uvcview-sdl		(SDL-based UVC viewer)
    branches
    tags
    trunk
  uvcview-qt		(Qt-based UVC viewer)
    branches
    tags
    trunk
  patches		(Patches for GnomeMeeting, Kopete, ...)

If that's not a good idea, feel free to kick me :-)

> Build was ok, with just one warning:
>
>   /home/speech/bornet/devel/work/misc/uvc/trunk/uvcvideo.c:2190:
>   warning: initialization from incompatible pointer type
>
> Attached patch uvc_v4l2_read.patch correct this warning.

Applied.

> Installing don't put the module in the right directory, but I think this
> is more related to GNU/Debian. (install in /lib/modules/2.6.13/ instead
> of /lib/modules/2.6.13-1-amd64-k8/).

I'm developping on a Gentoo box, and the module is installed in the correct 
location. If there's an easy way to fix the Debian problem without breaking 
other distributions, feel free to send a patch.

> Loading the driver seems OK:
[...]
> Then, I have try to access the camera with camstream, without success:
>
>   CVideoDevice::CVideoDevice() could not query capabilities; is this
>   really a video device?

camstream uses the deprecated V4L1 API, and the UVC driver only support V4L2.

> Accessing the camera with OpenCV
> (http://sourceforge.net/projects/opencvlibrary/) also cause problems...

Same problem.

> I'm now debugging these problems, because I want to use these camera
> with OpenCV. I will keep you informed on the progress.

You will have to implement V4L2 support in OpenCV.

> But to be sure that the webcam and driver is starting to work, could you
> please give me a pointer to a user program working with it ?

Here is a (very) basic test program which saves 100 frames to disk. You can 
change the resolution and format by modifying video_set_format (the camera 
supports V4L2_PIX_FMT_YUYV and V4L2_PIX_FMT_MJPEG). An SDL-based front-end 
will probably be added to the SVN repository in a few weeks time.

> Thanks in advance, and thanks a lot for starting this driver.

You're welcome.

Laurent Pinchart