[alsa-devel] In 3.8 kernel alsa only talks HDMI, hardware also has S/PDIF optical

Raymond Yau superquad.vortex2 at gmail.com
Tue Mar 12 08:26:03 CET 2013

> >
> > On my Asus P8H67-V there really are two physically
> > separate audio outputs. I have the optical port
> > connected to my receiver for when I want to pass
> > through the 5.1 audio tracks in movie files and
> > DVDs and the HDMI connected to the TV for more
> > ordinary audio (error beeps from the computer, etc).
> >
> > In kernel 3.7.9 I could output to both devices
> > (one at a time - never tried simultaneous).
> >
> > I've seen a bunch of patches in the archives that seem
> > to be related to this, but if fedora 18 has those patches,
> > they don't seem to be working.
> This is an intended change, considered as a "fix" for the formerly
> broken state.  The combination of SPDIF + HDMI has never been working
> properly because of conflicting control elements assignment.  (You may
> say that "it worked for me!", but it doesn't count it gets used right
> :)
> For fixing it, one of them has to be victimized.  Now IEC958 control
> element of SPDIF is shifted to the lone safe place for the sake of
> HDMI, which has more users than SPDIF, being persistent.
> Updating alsa-lib configuration from alsa-lib git tree should correct
> the usage of ICE958 control index for SPDIF devices.  Hopefully we'll
> get alsa-lib release sometime later...

Is IEC958 Default PCM Playback Switch specific for analog codec's spdif ?

control.32 {
iface MIXER
name 'IEC958 Default PCM Playback Switch'
value true
comment {
access 'read write'
count 1

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