From the ALSA wiki
The ATI IXP chipset works perfectly on 220.127.116.11 with Alsalibs 1.0.11. Sound mixing via ALSA and OSS works automagically, without the need for aoss. One trick is that in XMMS, make sure the device is set to default. Otherwise, it won't use dmix and will take complete control of the card. The only thing that is not tested is microphone input and micrphone mixing.