You're not using any special nVidia kext that would force HDMI audio? I don't know if such kexts would exist though. Need to maybe check my BIOS for audio settings, but I can't remember of anything from memory...
Aye, I have audio controller enabled in BIOS settings. Do you?
That was it. Thx.
It was disabled (as I am using an external USB audio dongle that requires no kexts).
I enable the onboard audio (and removed the USB audio).
I now have sound output. However, I have to manually choose rear green port or the front-panel headphone jack in Sound Pref.
That is, it does not auto-switch between the front & rear.
The rear mic input does not work.
The front mic input does not work.
Thus no FaceTime or Skype.
The sound output does work after waking from sleep.
I tried it with 10.9.1, 10.8.5 and 10.6.8 (yes I have three OS's on the system - nostalgia).
Does your mic input work (both front and rear) ?