XOs with no sound

Philipp Kocher philipp.kocher at gmx.net
Thu Jan 1 06:17:29 EST 2009


Happy New Year.

We don't use the Measure Activity.
Here are the most frequently used Activities using sound:
- Scratch version 11 (with resume sound problem, ticket #6201)
- Record version 59
- Browse version 98 with Adobe flash plugin version 10.0.12.36 (gnash
deinstalled) for a flash based English learning program
- Gcompris bundle Version 10
- Speak version 9

Recording with Scratch works with "No sound XOs" even so Capture volume 
is set to 0.

I will keep an eye on the alsamixer when I use these activities.

Regards,
Philipp

James Cameron wrote:
> 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?
> 



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