[LAD] alsa card order

[Lennart Poettering]

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? 

> 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

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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