An ALSA nightmare....

Mark Ellis mark.uzumati at virgin.net
Fri Aug 2 06:23:04 PDT 2002


On 2002.08.02 03:25 Steve Bougerolle wrote:
> 
> On Fri, 2002-08-02 at 09:59, Joel wrote:
> > I'm currently trying to get ALSA installed on my system ... and I
> must say
> > that it has been the most difficult to install of all the packages I
> have
> > tried. I completely gave up on v0.9.0, and changed over to v0.5.12a.
> 
> 
> Ok, first thing (maybe too late) is to go back to v0.9.  The 0.5
> series
> is deprecated and, believe it or not, on average has more problems.
> 

Definitely agreed, if you start down the 0.5 path you'll have to rebuild
everything that uses sound to upgrade to 0.9, not fun for a fulll 
system.

> I think
> > my current problem is that devfsd doesn't create the /dev/dsp by
> default,
> 
> Make sure you turned on OSS support when you compiled your drivers,
> AND
> make sure you load the OSS modules: snd-seq-oss, snd-pcm-oss and
> snd-mixer-oss.
> 
> That will make a device /dev/sound/dsp appear, along with a bunch of
> other devices (midi, mixer, sequencer).  Symlink those directly to
> /dev
> and your problems should disappear.
> 

try putting

alias /dev/dsp snd-pcm-oss

in your modules.conf, and turn on compatibility mode in devfsd.conf.

> > I don't want to have to run snddevices every time. I'd like to make
> devfsd
> > do the work that snddevices does by making changes to
> /etc/devfsd.conf, but
> > I'm not sure how to do it.
> 

devfsd is good when modules are loaded, but can be a bit tricky to use
with autoloading, hence the addition to modules.conf

> The snddevices script is definitely the WRONG solution for devfs.
> devfsd.conf should do it, but frankly I'm too lazy to mess with it and
> don't see any real advantage compared to making symlinks by hand, so I
> just stuck these lines in my startup script:
> 
> 		chown -R root.audio /dev/sound /dev/snd
> 		chmod -R ug+rwx /dev/sound /dev/snd
> 		chmod ugo+rwx /dev/sound/dsp /dev/sound/mixer
> 
> 		ln -sf /dev/sound/dsp /dev/dsp
> 		ln -sf /dev/sound/mixer /dev/mixer
> 

The only real advantage is removal of symlinks when modules are 
unloaded,
no biggie but cleaner. Just uncommenting the compatibility lines in
devfsd.conf will give you those symlinks. To set permissions in
devfsd.conf use something like :

REGISTER	^sound$		PERMISSIONS root.audio 0770
REGISTER	^sound/.*	PERMISSIONS root.audio 0770
REGISTER	^sound/dsp	PERMISSIONS root.audio 0777
REGISTER	^sound/mixer PERMISSIONS root.audio 0777
REGISTER	^snd$		PERMISSIONS root.audio 0770
REGISTER	^snd/.*		PERMISSIONS root.audio 0770

> The rwx permissions solve some weird problems I had way back in the
> foggy mists of history.  I'm not sure if you still need them with v0.9
> 

Mine are rwx for the directories and rw for the device files, seems to
work fine.

> > (I'm not certain if this script works right -- am I supposed to
> replace
> > [:space:] with some spaces -- how many?)
> 

Dont think you'll need that script if all the devfsd stuff is set up ok.

> The alsasound script it installs is a pain in the backside.  I hacked
> it
> out and wrote my own simpler one.  Just modprobe the relevant modules.
> 

If devfsd is set up right and you want autoloading, the boot script is
unnecessary, though you will need

post-install snd-sb16 /usr/sbin/alsactl restore
pre-remove snd-sb16 /usr/sbin/alsactl store

in modules.conf

If you dont want autoloading, then modprobing everything at boot is the
way to go.


I think i rambled in there, if it makes no sense then please say :) The
main point though is that if you're using devfsd you dont need a mknod
or manual symlink anywhere.

Mark
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