Logitech QuickCam Pro 9000 Audio

[Hans Petter Selasky]

On Wednesday 20 April 2011 21:12:57 Richard Kolkovich wrote:
> On Thu, Feb 17, 2011 at 12:53:28PM -0600, Richard Kolkovich wrote:
> > I have a Logitech QuickCam Pro 9000 which is detected by snd_uaudio just
> > fine (and webcamd, too!). The issue, though, is that I cannot manage the
> > recording volume.  I really only care about
> 
> > muting/unmuting, but mixer doesn't think there are any recording devices 
on this device:
> Looking into this again, it appears that the mixer *does* control the
> volume as expected - but 0 is not muted. If I set the mic volume to levels
> > 0, it is noticably louder. I cannot, of course, set it to a negative
> number. :)
> 
> Has anyone seen this sort of behavior on other audio devices (USB or
> not...)? Any ideas how to resolve it?
> 
> Cheers,

Hi,

Have a look at /sys/dev/sound/usb/uaudio.c .

USB Mixer control's range are part of the audio descriptors in the 
configuration descriptor. If 0 does not mean off, then maybe some bias value 
is computed wrong.

Compile kernel with options USB_DEBUG and enable hw.usb.uaudio.debug=15

Then look in dmesg for minimum and maximum mixer ctl. values.

--HPS