Installing MPD Disables OSS Driver

[SamK]

On a machine with a fully working OSS sound driver, subsequently installing mpd.tcz and re-booting, OSS no longer works.

Messages:
sudo soundon

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OSS is already loaded.

osstest

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Sound subsystem and version: OSS 4.2 (b 2002/201005121103) (0x00040100)
Platform: Linux/i686 2.6.33.3-tinycore #2012 SMP Wed May 12 17:05:42 EEST 2010


NOTICE! You don't have any audio devices available.
        It looks like your audio hardware was not recognized
        by OSS.
       
        If you have installed OSS just a moment ago then it may be necessary to.
        to rebot the system before trying to use the device(s).

ossinfo

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Version info: OSS 4.2 (b 2002/201005121103) (0x00040100) GPL
Platform: Linux/i686 2.6.33.3-tinycore #2012 SMP Wed May 12 17:05:42 EEST 2010 (box)

Number of audio devices: 0
Number of audio engines: 0
Number of MIDI devices: 0
Number of mixer devices: 0


Device objects
 0: osscore0 OSS core services
 1: oss_usb0 USB audio core services

MIDI devices (/dev/midi*)

Mixer devices

Audio devices

Nodes

On this machine filetool.sh is not used.
 

[TaoTePuh]

While I have no experience with OSS.

When I built mpd, I have also built support for OSS (see info-file). However, I've never tested - maybe someone else?

Probably the problem comes with the support for jack and pulseaudio. In the list of dependencies of jack and pulsaudio is also alsa. Now you have both sound systems (alsa and OSS). Just try the following :

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/usr/local/etc/init.d/alsasound start
speaker-test
When it roars, alsa has won the race ...

Need necessarily OSS?
AFAIK, OSS is "deprecated" since kernel > 2.4 and alsa is backward compatible with the extension alsa-oss.tcz  ...

[^thehatsrule^]

OSS here refers to v4+ (ie in the repo), not the old/legacy one.

[SamK]

[...]
Now you have both sound systems (alsa and OSS). Just try the following :...
[...]

On non-TC systems I have been able to get MPD to output directly to ALSA or OSS.  The reason to do it is on this particular TC machine is resource related.  On some systems using ALSA as an MPD output is known to produce a higher load on the CPU.  

Following discussions, with the MPD maintainer and others on the irc channel, a series of options for reducing CPU load have been suggested.  One is to use OSS in preference to ALSA.  

It is not a simple question of having both sound drivers installed and selecting the one that works. On some systems the gains made by reducing the CPU load via OSS may contribute towards being able to produce a usable system.
  

[curaga]

As can be seen in mpd.tcz.tree, mpd -> fluidsynth -> jack -> alsa. Please contact the maintainer of the Jack extension on why it depends on alsa.tcz (instead of merely libasound.tcz).

@SamK: on your local repo you can do

cd /path/to/tce/optional
sed -i '/alsa.tcz/d' *.dep

ie, remove alsa from all deps. Will last to an extension/dep update.

[TaoTePuh]

As already mentioned, alsa is also a dependency of pulseaudio (mpd -> pulseaudio -> alsa). But the command of curaga will delete this too.