I figured out how to get sound working on my MacPro5,1 (mid 2010). Here's that thread. Basically:
Part of this makes sense (which unit is the default), and part of it is magic(0=set 1=set). I gather this is turning on the first two gpio pins, but why this works is still pretty mysterious. I read in another thread here, about using hints such as:
and like any script-kiddie, I'm willing to give it a go, but I don't really have a clue as to what this does or how. I will gladly try it and if it works, use it, but I'd like to get a clue. Hence my latest question - where's the documentation, or put another way, how can I figure out what hints and what sysctls are applicable to my hardware?
Bash:
sudo vi /etc/sysctl.conf
dev.hdaa.0.gpio_config="0=set 1=set"
hw.snd.default_unit=3
Bash:
hint.hdaa.0.config="ovref"
hint.hdaa.0.gpio_config="0=set"