Logitech HD Webcam Pro c910 && snd_uaudio does not work

[Hans Petter Selasky]

On Sunday 13 May 2012 17:59:39 Matthias Apitz wrote:
> Hello,
> 
> The audio recording with the above cam is not working in r214444 and
> snd_uaudio(4); on plug-in it says:
> 
> May 13 17:22:36 tinyCurrent kernel: ugen4.4: <vendor 0x046d> at usbus4
> May 13 17:22:36 tinyCurrent kernel: uaudio0: <vendor 0x046d product 0x0821,
> class 239/2, rev 2.00/0.10, addr 4> on usbus4 May 13 17:22:36 tinyCurrent
> kernel: uaudio0: No playback!
> May 13 17:22:36 tinyCurrent kernel: uaudio0: Record: 32000 Hz, 2 ch, 16-bit
> S-LE PCM format May 13 17:22:36 tinyCurrent kernel: uaudio0: No midi
> sequencer
> May 13 17:22:36 tinyCurrent kernel: pcm1: <USB audio> on uaudio0
> 
> but recording does not work:
> 
> $ dd if=/dev/dsp1 of=/tmp/snd
> (after a second or so)
> dd: /dev/dsp1: Invalid argument
> 0+0 records in
> 0+0 records out
> 0 bytes transferred in 5.000931 secs (0 bytes/sec)
> 
> in /var/log/messages it says in that situation:
> 
> May 13 17:23:12 tinyCurrent kernel: pcm1: chn_read():
> pcm1:virtual:dsp1.vr0: record interrupt timeout, channel dead
> 
> The same procedure for recording works fine in r226986 (where uaudio is
> linked in the kernel) and
> 
> $ cat /tmp/snd > /dev/dsp
> 
> plays fine the recorded audio. Any idea?
> 
> Thanks
> 
> 	matthias

It might be a race. Try to delay starting webcamd, after snd_uaudio is loaded. 
I remember someone reported a similar issue to me, and the solution was that 
snd_uaudio must do some commands before the webcamd is started. Else it 
doesn't work. This is a bug in the Webcam itself.

--HPS