XOs with no sound

[James Cameron]

On Wed, Dec 31, 2008 at 03:52:05PM +0700, Philipp Kocher wrote:
> Alsa keeps the values in memory and writes it into the  
> /etc/alsa/asound.state file during shutdown. The file has a new  
> timestamp, so someone is writing into it at least.

Okay, that must be a build 767 thing.  Recent development builds use
/etc/asound.state only.  I've checked only the development builds at
this stage.

> Master Mono Playback Switch: is "false" should be "true" (line 50)
> Master Mono Playback Volume: is "0" should be "28" (line 61)

These two should have no effect.  I've tested that they have no effect
on audio playback.  The method I used was to temporarily install the OSS
module, and run a background process writing noise to the output.  Thus:

	modprobe snd-pcm-oss
	dd if=/dev/urandom of=/dev/dsp &

While this is running I then manipulated the controls using alsamixer.
The Master Mono Playback controls did nothing.

(Incidentally, the volume control keys on the keyboard changed the
Master control only, not the Master Mono control, and not the PCM
control.)

> PCM Playback Switch: is "false:false" should be "true:true" (line 178)

In "false:false" state, this switch prevents all sound output from
activities and applications.  The noise test above fell silent.

> PCM Playback Volume: is "0:0" should be "22:22" (line 190)

In "0:0" state, the audio is less loud, but not eliminated.  The noise
test continued to generate audio, but I needed to set the Master control
(not the Master Mono control) to at least 50%.

> Capture Volume: is "0:0" should be "15:15" (line 287)

In this state, the noise test audio is unchanged.  This would affect
sound capture using microphone though.

> I hope that helps.

Yes, it does.  It shows the immediate cause of the problem was that the
PCM Playback Switch was turned off.  That the Capture control was also
changed is interesting.

I've searched the installed activities on a development build here for
references to the amixer command.  The only activity that I've found it
used in is Measure.

Measure.activity/toolbar_side.py ... changes the Capture control.

Measure.activity/audiograb.py ... changes the PCM Playback Switch.

Is Measure being used?  Can you reproduce the symptom on a working XO by
asking for a shutdown while Measure is running?  What version of Measure
is being used?

Version 20 of Measure attempts to restore PCM to 70 on quit.  Does the
symptom clear if Measure is started and then quit?

-- 
James Cameron    mailto:quozl at us.netrek.org     http://quozl.netrek.org/