Support for the 889a appears to be rather wonky. From what I've been able to gather, the various incarnations of hacked Apple kexts derive key information from the drivers for the ALSA project in the linux world. ALSA has until recently had a bug wherein it would recognize ALC889a chipsets as ALC885. Consequently, the codec dumps many OSx86'ers have been relying on are likely wrong. Using Taruga's HDApatcher, and a better codec dump for a correctly identified 889a, I've managed to get 4 channels of input and 4 of output functioning well on my Gigabyte GA-EP35-DS4 r.2.1 motherboard with ALC889a codec running iDeneb 1.3 (10.5.5).

You can see my musings on the topic here;

http://www.infinitemac.com/f7/alc889a-codec-dump-t1105/

...where I have also posted the dump file that got me to this point.

In addition, I've edited the localizable strings in my kexts a bit to make them more friendly on my mobo. If anyone has the same board as me, and would like me to post my current kexts, I will.

Bear in mind that I am by no means an expert. I've simply done some reading, and kept at it. I'm sure there is a better way to approach this, and someone out there will doubtless correct these problems properly someday. Hopefully, Taruga himself will take up the challenge in the not-too-distant future.