[Alsa-user] Using dmix with multi

[Robert D. <di...@rp...>]

Is it possible to use dmix with multi?  I would like to be able to plug in 
external USB speakers and have playback continue through the default and USB 
speakers sound cards.  Putting dmix after multi results in silent 
failure.  Putting dmix anywhere in the chain before multi result 
in "ALSA lib pcm_direct.c:1464:(_snd_pcm_direct_get_slave_ipc_offset) Invalid 
type 'multi' for slave PCM".  I am using ALSA 1.0.14a.  I can get sound 
replicated on both sets of speakers when I take dmix out of the chain.

Thanks,

-Robert Dick-

----
pcm.multicard {
        type multi
        slaves.a.pcm hw:UA25
        slaves.a.channels 2
        slaves.b.pcm hw:Speaker
        slaves.b.channels 2
        bindings {
                0.slave a; 0.channel 0
                1.slave a; 1.channel 1
                2.slave b; 2.channel 0
                3.slave b; 3.channel 1
        }
}

pcm.!dmix {
        type dmix
        ipc_key 1234
        slave.pcm multicard
}

pcm.asymed {
        type asym
        capture.pcm dsnoop
# If I change this to dmix, it fails.
        playback.pcm multicard
}

pcm.!default {
        type plug
        slave.pcm asymed
        route_policy duplicate
}