I am trying to get AppleHDA working on Biostar G41-M7 (using ALC662), although sound preference shows all inputs and outputs, no sound come out, no mic work either. Need some advice.

Here are the details:
1) Vanilla AppleHDA (1.7.4a1 from 10.6.1) + DSDT + LegacyAppleHDA,
a. sound preference shows all outputs: Headphone, Internal speaker, Digital out, volume control is presented (can change), mute control is presented (can toggle), but NO sound come out,
b. Internal Mic and Line are shown in input panel, Mic does not work either, (haven't tried LineIn, I doubt it will work)
c. No "sound assertion" in kernel.log

2) Patched AppleHDA (1.8.7f1, from 10.6.4, only patched from 10ec0885 to 10ec0662) + DSDT + LegacyAppleHDA,
a. Same as previous case, sound preference show correctly, but NO sound (removed digitial out, it causes some sound assertion)
b. Mic does not work, (removed line-in, it causes problem due to widget cap)
c. Only clue is a sound assertion:
Sound assertion "mFirstConvert && ( numSampleFrames > currentSampleFrame)" failed in "/SourceCache/AppleHDA/AppleHDA-187.4.1/AppleHDA/AppleHDAEngine.cpp" at line 1816 goto Exit
d. Changing output from Headphone to Internal Speaker will cause kernel panic, screen points to a function inside com.apple.driver.DspFuncLib caused the KP.

3) using reggie_se to probe all NodeIDs, all of them seems correctly configured,(with mute and gain control correctly set by AppleHDA driver)

Your input is highly appreciated!