Hi Julian,

On Saturday 12 April 2008, Julian Oliver wrote:
> hi,
>
> i have a Quickcam Pro 9000 and will be using it in an electronic art
> exhibition in the computer vision component. while the driver
> performance under is certainly great - even at 960x720 - i've had little
> luck using uvcdynctrl-0.2 (latest svn). i would like to use it so that i
> can turn off autoexposure when the gallery assistants reboot the machine
> as luvcview is not an option for them. no module params seem to be
> exposed either, at least from modinfo's perspective.
>
> this is the output i'm getting:
>
>     $ uvcdynctrl -l
>     [libwebcam] Unknown V4L2 control ID encountered: 10094849
>     [libwebcam] Unknown V4L2 control ID encountered: 10094850
>     [libwebcam] Unknown V4L2 control ID encountered: 10094851
>     Listing available devices:  video0   UVC Camera (046d:0990)
>
> while i can set some controls using uvcdynctrl, like Sharpness, i cannot
> get or set others (like 'Exposure, Auto'):
>
>     $ uvcdynctrl-0.2 -v --get="Exposure, Auto"
>     [libwebcam] Unknown V4L2 control ID encountered: 10094849
>     [libwebcam] Unknown V4L2 control ID encountered: 10094850
>     [libwebcam] Unknown V4L2 control ID encountered: 10094851
>     ERROR: Unknown control specified.
>
> despite this control appearing in --clist output.
>
> any tips here? something i'm missing?
>
> i'm building against:
>
>     2.6.24-1-686

This is a known problem:

"Important note: libwebcam 0.1.1 is not fully compatible with revisions of the 
UVC driver later than 178. Until libwebcam 0.1.2 is available, users are 
advised to use uvcvideo r178."

(http://www.quickcamteam.net/software/libwebcam/)

Control IDs have recently changed in the driver to match new controls 
introduced in the V4L2 API. Now that the UVC standard controls are part of 
the official V4L2 API, they shouldn't change anymore.

As a quick & dirty workaround, try to recompile libwebcam (0.1.1) with 
uvcvideo.h and uvc_compat.h from the driver sources. You will run into 
compilation issues in libwebcam.c. Commenting the 2 faulty lines should work 
around the problem.

For uvcdynctrl and libwebcam issues, you might get more help in the 
quickcamteam.net forums.

Best regards,

Laurent Pinchart
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