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

Takashi Iwai tiwai at suse.de
Tue Mar 12 08:09:08 CET 2013

At Mon, 11 Mar 2013 19:18:01 -0400,
Tom Horsley wrote:
> See https://bugzilla.redhat.com/show_bug.cgi?id=919630
> for details.
> Comment 4 in that bug is from someone who says it looks
> like the driver only created the HDMI and not the separate
> optical S/PDIF output.
> 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...


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