I have a 1.6.2 system with the following sound card:

auich0 at pci0 dev 31 function 5: i82801DB/DBM (ICH4/ICH4M) AC-97 Audio
auich0: interrupting at irq 5
auich0: ADS112 codec; headphone, 20 bit DAC, no 3D stereo
auich0: measured ac97 link rate at 48000 Hz
audio0 at auich0: full duplex, mmap, independent

In order to support this card, I grabbed auich.c and auichreg.h from
the NetBSD-1.6-release sources.  The sound card is found and everything
appears to work, but there is no audio output.  Does anybody have any
suggestions?