Comment 7 for bug 1078924

>>…where would I start reading up on configuration of alsa?

http://git.kernel.org/?p=linux/kernel/git/tiwai/sound.git;a=blob_plain;f=Documentation/sound/alsa/HD-Audio-Controls.txt;hb=HEAD

IDT/Sigmatel codecs
-------------------

* Analog Loopback
  This control enables/disables the analog-loopback circuit. This
  appears only when "loopback" is set to true in a codec hint
  (see HD-Audio.txt). Note that on some codecs the analog-loopback
  and the normal PCM playback are exclusive, i.e. when this is on, you
  won't hear any PCM stream.

* Swap Center/LFE
  Swaps the center and LFE channel order. Normally, the left
  corresponds to the center and the right to the LFE. When this is
  ON, the left to the LFE and the right to the center.

* Headphone as Line Out
  When this control is ON, treat the headphone jacks as line-out
  jacks. That is, the headphone won't auto-mute the other line-outs,
  and no HP-amp is set to the pins.

* Mic Jack Mode, Line Jack Mode, etc
  These enum controls the direction and the bias of the input jack
  pins. Depending on the jack type, it can set as "Mic In" and "Line
  In", for determining the input bias, or it can be set to "Line Out"
  when the pin is a multi-I/O jack for surround channels.