"For the testing done in this article we were using
Ubuntu 8.10 with the Linux 2.6.27 kernel and the default ALSA
1.0.17 and later on we had built ALSA 1.0.18a. Earlier this year
ALSA had also picked up R700 HDMI audio support, which means both
Radeon HD 2000/3000 and Radeon HD 4000 owners can use the audio
processor found on their graphics card under Linux. Though in a few
configurations we tested, the audio would not work properly. The
HDMI display we used was a Toshiba Regza 32RV530U 32" LCD HDTV.
"The Catalyst 8.11 driver had no problems reading the TV's EDID
data and properly setting its mode to the native 1080p resolution,
but the audio once again was not working. The HDA ATI HDMI audio
adapter was detected, but when trying to make that the default
audio device and adjusting its volume, there was no audio being
outputted. We had tried different ATI R600 and R700 graphics cards
and it was to no avail."