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Re: alsa not working

On Fri, 11 Jun 2004 23:42:52 +0200
John van Spaandonk <j.spaandonk@chello.nl> wrote:
> On Friday 11 June 2004 22:06, Chris Metzler wrote:
>> Your problem is that you are loading OSS modules.  The ALSA modules
>> can't load if the OSS modules are installed.  First, remove the OSS
>> modules from your /etc/modules file, so they'll stop being loaded
>> automatically during boot.  Then, check to see if you have either
>> discover or hotplug installed.  During boot, their scripts run before
>> the ALSA script does, and they'll try to install OSS modules.  If
>> you have either or both of them installed, make sure that the OSS
>> modules are blacklisted in their respective configuration files.
>> The ALSA modules will load appropriately.
> Chris, thanks for this tip.
> It seems a very reasonable hypothesis.
> One question: how do I recognise OSS modules?
> Did you see any in my lsmod output?

Yes.  From your lsmod output:

}Module                  Size  Used by    Not tainted
			[ snip ]
} mpu401                 21092   0 (unused)

OSS module to handle the external MIDI port.

} emu10k1                64780   2

OSS module to handle the audio controller on your soundcard.

} sound                  61984   0 [mpu401 emu10k1]

Top-level OSS module.

} soundcore               4420   7 [emu10k1 sound]

Module that provides sound capabilities to the kernel.  You need
this one regardless of whether you're using OSS or ALSA.

} ac97_codec             13784   0 [emu10k1]

OSS module to handle the AC97 codec (mixer, DAC/ADC, etc.) on
your soundcard.

ALSA modules have "snd_" at the beginning.  Someone who has
a Soundblaster Live will have sound modules that look like
this (sorted):

} snd                    33796   0 [snd-seq-midi snd-emux-synth
snd-seq-virmidi snd-seq-oss snd-seq-midi-event snd-seq snd-pcm-oss snd-mixer-oss snd-emu10k1 snd-pcm snd-timer snd-hwdep snd-util-mem snd-ac97-codec snd-rawmidi snd-seq-device]
} snd-ac97-codec         48300   0 [snd-emu10k1]
} snd-emu10k1            75332   1 [snd-emu10k1-synth]
} snd-emu10k1-synth       4860   0 (autoclean) (unused)
} snd-emux-synth         28348   0 (autoclean) [snd-emu10k1-synth]
} snd-hwdep               5248   0 [snd-emu10k1]
} snd-mixer-oss          13104   1 [snd-pcm-oss]
} snd-page-alloc          6228   0 [snd-emu10k1 snd-pcm]
} snd-pcm                61892   0 [snd-pcm-oss snd-emu10k1]
} snd-pcm-oss            37956   0
} snd-rawmidi            14240   0 [snd-seq-midi snd-seq-virmidi snd-emu10k1]
} snd-seq                38448   2 [snd-seq-midi snd-emux-synth snd-seq-midi-emul snd-seq-virmidi snd-seq-oss snd-seq-midi-event]
} snd-seq-device          4256   0 [snd-seq-midi snd-emu10k1-synth snd-emux-synth snd-seq-oss snd-seq snd-emu10k1 snd-rawmidi]
} snd-seq-midi            4000   0 (autoclean) (unused)
} snd-seq-midi-emul       4944   0 (autoclean) [snd-emux-synth]
} snd-seq-midi-event      3584   0 [snd-seq-midi snd-seq-virmidi snd-seq-oss]
} snd-seq-oss            29632   0 (unused)
} snd-seq-virmidi         3320   0 (autoclean) [snd-emux-synth]
} snd-timer              15588   0 [snd-seq snd-pcm]
} snd-util-mem            1280   0 [snd-emux-synth snd-emu10k1]

(I compile soundcore into my kernel rather than use it as a module,
which is why it's not listed here as well).

> BTW I had installed discover just tonight, to see if it would help;
> obviously I'm better of without it if I want to use ALSA.

Well, I have it installed; you just need to configure it to not load
the OSS modules, which is very straightforward.  Look at the man
pages for discover, discover-modprobe, and discover-modprobe.conf.

> I also use hotplug, which gives me lots of error messages but seems
> to work with USB anyway. It says PCI events are not synthesised, so I
> guess I do not really have to worry about hotplug for the sound card?

I dunno.  I don't really understand hotplug myself.  I've just heard
other people here (typically, people with 2.6 kernels) talk about having
to make sure hotplug didn't load OSS modules.  

> On a related note, isn't it time for the discover program to start 
> installing ALSA over OSS? Or does Debian use ALSA as a default only for 
> the 2.6 kernel?

It's not Debian, but rather the kernel folks, who indicated that OSS
was the default sound infrastructure up through the 2.4 kernels, and
ALSA starting with 2.6.  But I agree that discover either ought to
favor the ALSA modules if they're present too, or should ask about it
in its initial configuration (and maybe that's something that could
be implemented through debconf, dunno).


Chris Metzler			cmetzler@speakeasy.snip-me.net
		(remove "snip-me." to email)

"As a child I understood how to give; I have forgotten this grace since I
have become civilized." - Chief Luther Standing Bear

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