[Freedreno] hdmi audio on ifc6410

[Rob Clark]

fyi, I've managed to get hdmi audio (mostly) working, on the inforce
board.  I expect that basically the same thing should work on bstem as
well.

I've untangled the msm alsa/soc driver from ION and fixed a few issues
with it along the way.  What I have is still a bit work-in-progress,
but I've pushed to here:

  https://github.com/freedreno/kernel-msm/commits/ifc6410-drm-hdmi-audio
  git://github.com/freedreno/kernel-msm.git ifc6410-drm-hdmi-audio

(and may I add, the sound/soc/msm stuff is a royal PITA to debug!)

There are a couple rough edges:

1) Shows up as 'Analog Output' in gnome sound control panel.. I'm not
much of an audio expert but I think this is a symptom of pulseaudio
not properly recognizing things.  Maybe we need some pulseaudio config
files so that it properly understands the audio routing options?

2) Glitch at beginning of playback.. probably I need to do something
to synchronize w/ audio engine before enabling audio packets on the
hdmi side of things.  Need to sort out how that works.


for folks who want to try it out, I've also put a pre-built kernel here:

  http://people.freedesktop.org/~robclark/f20/ifc6410-boot-audio.img

and my alsa config:

  http://people.freedesktop.org/~robclark/f20/asound-hdmi.state

to apply my config on your board:

  sudo alsactl restore -f asound-hdmi.state

If you know anything about SoC audio + pulseaudio, I could certainly
use some help sorting out the audio configuration/routing mess.. it's
something pretty far outside of my area of expertise.

BR,
-R