[LAD] alsa card order

drew Roberts zotz at 100jamz.com
Wed Apr 29 01:22:29 UTC 2009


On Tuesday 28 April 2009 19:34:52 Lennart Poettering wrote:
> On Wed, 29.04.09 00:18, Fons Adriaensen (fons at kokkinizita.net) wrote:
> > On Tue, Apr 28, 2009 at 11:59:36PM +0200, Lennart Poettering wrote:
> > > On Tue, 28.04.09 23:36, Fons Adriaensen (fons at kokkinizita.net) wrote:
> > > > Hello all,
> > > >
> > > > I'm Running F10 and I have these lines in /etc/modprobe.conf:
> > > >
> > > > options snd cards_limit=4
> > > > alias snd-card-0 snd_intel8x0
> > > > alias snd-card-1 snd_mpu401
> > > > alias snd-card-2 snd_ice1712
> > > > options snd-card-0 index=0
> > > > options snd-card-1 index=1
> > > > options snd-card-2 index=2
> > > >
> > > > but the order of the devices is always the
> > > > inverse: ice1712, mpu401, intel8x0
> > >
> > > Since F10 ALSA card indexes are not stable anymore to allow flexible
> > > hotplugging setups.
> >
> > I know, but
> >
> > 0. I've had flexible hotplugging setups before,
> >    so what's the point ?
>
> The point is that if you plug in a new sound card for which you
> haven't configured such a modprobe.conf line it will take up the first
> available index which might then collide with your configuration for
> later plugged in devices. We had quite a few bugs about this
> reported. This problem is amplified by the fact that we now initialize
> drivers in parallel at bootup.
>
> Doing these things with indexes is just broken. It's like network
> interfaces. Everybody learned to use names for them instead of the
> low-level ifindex. Now it's time people learn the same for audio
> devices.
>
> The naming system exists for a reason, i.e. to allow you to easily
> identify devices without remembering any cryptic numbers. It also
> allows you to change the name during runtime via sysfs in case you
> want to fix them up.
>
> > 1. I *want* stable indices, and
>
> Why?

Well, I don't care how I would do it so long as I can finally find a way to do 
it.

I want to load up 1 box with 4 sound cards (preferably el cheapo USB cards) 
and hoot the outputs of 4 radios to the inputs of the cards. (I prefer 
identical cards if possible.) I want to tune each radio to a different 
station and record each 24x7. now I want the stations to record consistently.

So far I have not run across a solution that didn't assume different cards. 
Any ideas anyone/
>
> > 2. according to the info on the CCRMA site the
> >    modproble lines above should give me stable
> >    indices. If not, has ALSA been mutilated to
> >    ignore these lines ?
>
> No, we didn't change ALSA like that.
>
> Lennart

all the best,

drew



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