[Intel-gfx] HDMI Audio Channels mis-detected on i915

[Jeremy Bush]

Hi Fengguang- 

On May 23, 2011, at 8:32 AM, Wu Fengguang wrote:

> Hi Jeremy,
> 
>> I have my machine hooked up to an Onkyo TX-SR607 7.2-Channel receiver. Yet when the machine boots,  HDMI detection mis-detects the hardware on the other end of the HDMI cable:
>> 
>> [ 2.090473] HDMI: detected monitor at connection type HDMI
>> [ 2.090475] HDMI: available speakers: FL/FR
>> [ 2.090477] HDMI: supports coding type LPCM: channels = 2, rates = 44100 48000 88200, bits = 16
>> [ 2.090480] HDMI hot plug event: Pin=6 Presence_Detect=1 ELD_Valid=1
> 
> That information is filled by BIOS or VBIOS. There are 3 possibilities
> 1) BIOS provides some dumb EDID-Like Data (ELD) regardless of the HDMI sink
> 2) BIOS does not parse EDID correctly
> 3) your TX-SR607 EDID data is broken
> 
> I'm writing a drm patch to do ELD for audio in the graphics driver,
> which will address problems caused by (1) and (2). I've done the
> scratch patch, but will need more tests before sending it out.
> 
> For now you may still manually correct ELD with this command:
> 
>        echo speakers 0 > '/proc/asound/card0/eld#3.0'
> 
> By clearing the speakers setting, the audio driver will assume your
> HDMI sink supports all speakers.

This worked. I also had to adjust the sad0_channels key. I was able to do speaker-test -c 8 and play 7.1 audio without bitstreaming.

> 
>> Is this a known problem?
>> 
>> My machine specs are as follows:
>> 
>> Intel i3 2100T
>> MSI H67MA-E45 (with Realtek ALC892 audio chip)
>> 
>> I'm using HDMI output only.
> 
> Will you try the above workaround command first? For the long term
> solution, if you are ready to compile new kernels, I can send you the
> patch for testing.

Please send it over :)

Thanks for the help,

Jeremy