[Alsa-user] Audio routes with SB Live (emu10k1)?

[Dast <da...@sa...>]

Hello all,

I was hoping someone could help me with this.

My setup:

Gentoo 2005.0
Kernel - 2.6.11-r9 (with ALSA built in, version 1.0.8 IIRC)
Soundcard - Soundblaster Live (emu10k1) + Live Drive connected to
external receiver via the digital, optical output (toslink)

My situation:

This is my first experience with ALSA, so please forgive me if this is
a stupid question.  In the past, I've been using OSS with my SB Live
(for quite a while, actually), but I am eager to move to ALSA if
possible.  There is only one thing holding me back.  After digging for
information on this for over a week, I've just about given up, but I
was hoping someone here might know the answer.

First off, I've gone through all of the standard ALSA setup, and the
SB Live works, including the Live Drive.  ALSA enables the digital,
optical output and I get sound out of it fine to my external receiver.
I even got the RM-900 remote control working.  No problem.

However, there is one last thing that I can not figure out how to
configure.  I need to route the optical, digital input on the Live
Drive back out through the optical, digital output on the Live Drive.
I do this in order to mix the output of various programs like XMMS
with various sources coming in via the optical input back out through
the optical output.  Anything coming in through the optical input gets
routed to optical output passively, and if I happen to play any audio
on the PC, it gets mixed in as well.  (Everything I do is in stereo,
BTW, no multichannel content.)

In OSS, I do this with the emu-dspmgr utility with one call:

emu-dspmgr -a"Opt. Spdif:Digital"

This sets an internal route on the emu10k1 from the optical input out
through the optical output.  Being that the PCM input is already
routed to Digital by default, I get the mixed output I want.

Can anyone tell me how to do the equivalent under ALSA?

I've searched through the docs at www.alsa-project.org, I've googled,
and I've searched the mailing list archives, all to no avail.

Can anyone clue me into how to do this?  Does this require a change to
the emu10k1 driver sourcecode, or can I accomplish this through an
asound.conf incantation?

Thanks in advance,
-- 
--Dast

 "Trust the man with the corrective lenses."
  Large Professor