HDMI audio on R500

[Alex Deucher]

On Fri, Jun 5, 2009 at 10:51 PM, Russ Dill <russ.dill at gmail.com> wrote:
> On Mon, Mar 23, 2009 at 4:20 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
>>
>> On 3/23/09, Russ Dill <russ.dill at gmail.com> wrote:
>> > On Mon, Mar 23, 2009 at 3:29 PM, Alex Deucher <alexdeucher at gmail.com> wrote:
>> >  > 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
>> >
>> >
>> > Attached
>> >
>> >
>>
>> Looks pretty standard; internal tmds used for hdmi port.  I suspect
>> hdmi audio is implemented via some oem-specific solution.
>
> I had a chance to find the chip that powers this. Its a Silicon Image
> TMDS ParallelLink Sil 1930.
>
> http://www.siliconimage.com/docs/1390_1930_1368_FINAL.pdf
>
> The product brief says that it connects with I2S, S/PDIF, or HD-Audio
> to the audio codec and I2C to the GPU. I'm not sure if the GPU
> controls the audio pass-through via I2C or not.
>
> I don't think any datasheets are publicly available.
>

It'll be tough without docs or knowing how it's wired up.

Alex