I'm running a -current kernel (1.5S) and userland from about four days ago
on my Dell OptiPlex GX110. The onboard audio works wonderfully for CD
playthrough, but not for audio files. Do I need to somehow configure the
audio device? (The onboard audio on my previous machine Just Worked.)

More info:

# audioplay something.au
audioplay: failed to open /dev/audio: Invalid argument

# ls /dev/audio*
lrwx------  1 root  wheel        6 Feb 23 15:58 /dev/audio -> audio0
crw-rw-rw-  1 root  wheel  42, 128 Feb 23 15:58 /dev/audio0
crw-rw-rw-  1 root  wheel  42, 129 Feb 23 15:58 /dev/audio1
crw-rw-rw-  1 root  wheel  42, 130 Feb 23 15:58 /dev/audio2
crw-rw-rw-  1 root  wheel  42, 131 Feb 23 15:58 /dev/audio3
lrwx------  1 root  wheel        9 Feb 23 15:58 /dev/audioctl -> audioctl0
crw-rw-rw-  1 root  wheel  42, 192 Feb 23 15:58 /dev/audioctl0
crw-rw-rw-  1 root  wheel  42, 193 Feb 23 15:58 /dev/audioctl1
crw-rw-rw-  1 root  wheel  42, 194 Feb 23 15:58 /dev/audioctl2
crw-rw-rw-  1 root  wheel  42, 195 Feb 23 15:58 /dev/audioctl3

# dmesg | grep auich
auich0 at pci0 dev 31 function 5: i82801AA (ICH) AC-97 Audio
auich0: interrupting at irq 10
auich0: Analog Devices AD1881 codec; headphone, Analog Devices Phat Stereo
audio0 at auich0: full duplex, mmap, independent

# audioctl -a
name=ICH AC97
version=0x02
config=auich0
encodings=
properties=full_duplex,mmap,independent
full_duplex=0
fullduplex=0
blocksize=384
hiwat=170
lowat=127
monitor_gain=0
mode=
play.rate=8000
play.channels=1
play.precision=8
play.encoding=mulaw
play.gain=127
play.balance=32
play.port=0x0
play.avail_ports=0x0
play.seek=0
play.samples=0
play.eof=0
play.pause=0
play.error=0
play.waiting=0
play.open=0
play.active=0
play.buffer_size=65536
record.rate=8000
record.channels=1
record.precision=8
record.encoding=mulaw
record.gain=191
record.balance=32
record.port=0x1
record.avail_ports=0x7
record.seek=0
record.samples=0
record.eof=0
record.pause=0
record.error=0
record.waiting=0
record.open=0
record.active=0
record.buffer_size=65536
record.errors=0