I've been trying to get this audio to work properly for a few weeks now, so far unsuccessfully.
Here's where I'm at:I've edited my DSDT properly, I dumped my codecs and got my verbs, I tried to patch my own AppleHDA (but I failed miserably , so instead I downloaded one of two 10.8.2 ALC887 AppleHDA.kexts found on osx86.net, though I only replaced the binary, since I had already edited my layout and pathmaps and pin configs) With that, I boot and get a single sound assertion from AppleHDAController (I've noticed a few others triggered under specific circumstances: trying to change the sample rate or bit-depth in the Audio/MIDI Setup, for example) but otherwise AppleHDA appears to load properly.
My IOReg shows AppleHDA and all its components loaded, it shows several HDAStreams, etc etc. In devices, I can see a Line-in, Speakers, a Line-Out and a Digital Out.
If I connect my headphones to the appropriate port and try changing the output volume I get a single, relatively loud "POP" and then nothing. So, it happens the first time a sound would be output through the phones after being plugged in, basically.
And I have tried editing everything I can think off, with no success. Either I break it and the Devices stop showing or just nothing changes.
Attached are the a screenshot , the DSDT I'm using and the IORegistry. So far, the only "weird" thing I've been able to notice is under "AppleHDADriver", the "PowerProfile" has "CurrentPowerLevel", "IdlePowerLevel" and "MaxPowerLimit" all set to 0x0. I have no idea if this is at all related but from the symptoms it seems to me like it could be a power issue?
If not, maybe someone else will have a better answer?