HDMI audio on R500

[Alex Deucher]

On 3/23/09, Russ Dill <russ.dill at gmail.com> wrote:
> I have a laptop with an HDMI output. In Vista, I can get the Realtek
>  HD audio driver to pass audio through the HDMI interface. In Linux, no
>  amount of fiddling with IEC958 switiches and PCM devices will get
>  audio to come through the HDMI interface.
>
>  00:00.0 Host bridge: ATI Technologies Inc RS480 Host Bridge (rev 10)
>  [...]
>  00:14.2 Audio device: ATI Technologies Inc IXP SB4x0 High Definition
>  Audio Controller (rev 01)
>  [...]
>  01:00.0 VGA compatible controller: ATI Technologies Inc M56P [Radeon
>  Mobility X1600]
>
>  An alsa developer was thinking that since the video chip interfaces
>  with the TMDS encoder chip and must somehow be involved. Is anyone
>  aware of any registers or bits that would enable HDMI audio
>  pass-through?

Native HDMI audio support is only available on RS6xx/R6xx/R7xx chips.
I suspect there is either some platform specific magic required in to
get it to work (i.e., some external component does the audio/video
mixing), or your laptop's oem used an external hdmi encoder.  Can you
send me your video bios?

as root:
cd /sys/bus/pci/devices/<pci bus id>
echo 1 > rom
cat rom > /tmp/vbios.rom
echo 0 > rom

Alex