[Gta04-owner] QtMoko v48 sound problems

Radek Polak psonek2 at seznam.cz
Sun Oct 28 21:59:36 CET 2012

On Sunday 28 October 2012 00:03:38 EdorFaus wrote:

> All this makes me wonder if, since the mediaserver process likes to hog
> the sound card, it would be more practical to make it apply the ALSA
> state files itself, instead of calling out to alsactl?

Yes, we are using alsactl because it was easiest way to implement (and same 
way it was already done by Trolltech for Freerunner).

It would be best to use alsa api for this and change only the controls that 
differ between the two states.

However alsactl is probably not really causing the problem here, since it 
works nice on Freerunner.

> Hm, maybe it would be easier to have a way of making the mediaserver
> close its connection on demand? E.g. a signal (SIGUSR1 maybe?) that
> makes it stop whatever it's doing and close the device immediately?

This could work nice. Btw the state switching is done by mediaserver too so we 
might not even need IPC here...

> (Or... is that what we have now, except it doesn't work right? I guess I
> should take a look at the code before I start handing out random
> suggestions like this...)

I have now working gstreamer based media engine. So trying to fix cruxus can 
be wasted time.

So far the gstreamer engine seems to close the sound card properly, but i have 
it working for just few minutes, so more testing is needed.

There are few more good things about gstreamer - it looks well supported, it 
can play videos in media player, it's used also by webkit and it can use dsp 
to accelerate the decoding.

Btw has anyone succeeded with dsp accelerated gstreamer? I have followed this 
[1] and i could finish the install fine, but i couldnt make gst-launch to use 

[1] http://elinux.org/BeagleBoardDebian#DSP

> I remember seeing a suggestion about using PulseAudio - and PA does have
> a way of doing that latter suggestion, even provides a CLI tool for
> doing it. It is used similarly to sudo: "pasuspender <command>" that
> makes PA release the sound card as long as the <command> is running. So,
> instead of running "alsactl restore -f <file>" directly, you'd run
> "pasuspender -- alsactl restore -f <file>".

I was trying to use pulseaudio for gsm audio routing, but i didnt have much 
luck. Otherwise pulseaudio could be nice for sound mixing. There is also 
plugin in qtmoko which uses pulseaudio instead of alsa. But for now i'd like 
to focus on gstreamer->alsa.



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