Comment 58 for bug 1236965

On page 85 of p180hm_svc_manual.pdf , there is a diagram that shows how the subwoofer and center-speaker are wired up.
ALC892 pin 43&44 aka 'port G' is hooked into the PI5A3158, and from there into the TPA2008 amp...
http://www.pericom.com/products/signal-switch-ic-multiplexers/?part=PI5A3158
Dual single-pole dual-throw mux/de-mux switch.... The wire controlling the PI5A3158 is called 'DOLBY_SEL'

The control-signal is emitted by the IT8519 chip, on pg90 of the pdf, which is the keyb/smbus/lpc/gpio/uart/rtc/adc/dac/etc chip.

There is a similar PI5A3158 chip used to wire up the surround-out-left and surround-out-right speakers, aka rearLeft/rearRight.
And the control wire has the same label... so maybe we are already properly controlling DOLBY_SEL for rearLeft/rearRight, since those seem to work fine, and we therefore just need to apply the same sort of control when trying to activate frontCenter/subwoofer?