Christian König has released his latest HDMI audio patch on the RadeonHD mailing list
. With the ATI R600 GPUs and later having an integrated APU (Audio Processing Unit), when using an HDMI connector it's possible to use your Radeon graphics card for sound too. There's been patches in ALSA
for the sound support, but additional code is needed within the open-source X.Org drivers too. At this time neither the xf86-video-ati
have support for the integrated audio, but on the RadeonHD side there have been these patches maintained by Christian.
Christian's latest RadeonHD HDMI audio patch is over 60KB in size and is over 2,000 lines. As AMD hasn't released any documentation covering the registers for HDMI audio, he had reverse-engineered them. This most recent patch has a few fixes and enabled HDMI audio by default. The audio support though can be disabled from the xorg.conf
This HDMI audio support has been tested and verified on the RV620, RV630, RV635, RV770, RS780, and M86 GPUs. Ideally we will see this patch merged into the xf86-video-radeonhd driver in the near future.