[alsa-devel] ALSA Multichannel through HDMI

[John Ettedgui]

On Thu, Nov 25, 2010 at 2:58 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
> On 26.11.2010 00:42, John Ettedgui wrote:
>> On Thu, Nov 25, 2010 at 11:19 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>> On 25.11.2010 14:21, John Ettedgui wrote:
>>>> On Thu, Nov 25, 2010 at 3:40 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>> On 25.11.2010 13:09, John Ettedgui wrote:
>>>>>> On Thu, Nov 25, 2010 at 2:49 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>>>> On 25.11.2010 06:12, John Ettedgui wrote:
>>>>>>>> I'm actually trying to get a 5.1 setup working without passthrough, if
>>>>>>>> I use mplayer with passthrough my receiver behaves just fine, but I am
>>>>>>>> trying to send the 6 channels from the computer.
>>>>>>>>
>>>>>>>> I was actually told that the current ALSA driver for radeon's hdmi
>>>>>>>> does not support more than 2 channels, and that would explain why I'm
>>>>>>>> getting this behavior. Is that true though?
>>>>>>>
>>>>>>> Yes.
>>>>>>>
>>>>>>>
>>>>>>> However, strangely your log output seems to show the intel's hdmi parser
>>>>>>> being used instead:
>>>>>>>
>>>>>>>> ALSA sound/pci/hda/patch_intelhdmi.c:842: hdmi_setup_stream: NID=0x2,
>>>>>>>> stream=0x1, new-format=0x11
>>>>>>>
>>>>>>> Were you just trying some patch at the time?
>>>>>>
>>>>>> yes Wu gave me a patch to try against the kernel, I'm guessing this is
>>>>>> the reason you see something unexpected.
>>>>>
>>>>> Did 6 channels work with that patch? (possibly with a wrong channel order)
>>>> Not any better as far as I remember.
>>>
>>> OK. Did 2 channel audio continue to work with it?
>>>
>>> If you are not sure, here's the patch doing the same thing against
>>> current alsa driver:
>>> http://stuff.onse.fi/0001-ALSA-hda-Use-generic-HDMI-code-for-ATI-HDMI-codecs.patch
>>>
>>> Confirming that would help (it would allow to switch the ATI chip to use
>>> the generic parser instead of the ATI-specific one), though not with the
>>> multichannel issue (see below).
>>>
>>> [...]
>>>
>>>>>> Since I just moved to jack/rca cables I'm in no hurry anymore, but is
>>>>>> there any reason why the driver cannot work with more than 2 channels?
>>>>>
>>>>> I don't really know (it is simply not implemented).
>>>> Alright.
>>>>>
>>>>>> Anything I could do to help with that?
>>>>>
>>>>> Possibly. But see above, so that we won't try the same things you
>>>>> already tried :)
>>>>>
>>>> Sure :)
>>>
>>> Looking again at the the alsa info output you provided, I don't think I
>>> have any great ideas. It looks like the chip simply reports that it
>>> supports a maximum of 2 channels.
>>>
>>> One option could be hardcoding "chans = 8;" in generic_hdmi_build_pcms()
>>> in sound/pci/hda/patch_hdmi.c (assuming you have the above patch and 2
>>> channel audio works with it). However, I find it rather unlikely that it
>>> would make any difference.
>>>
>>> --
>>> Anssi Hannula
>>>
>>
>> Anssi,
>> the patch fails on my kernel, I cannot find the hda_codec_preset
>> manually in there either.
>> Did you want me to try that against a 2.6.37 rc instead of a 2.6.36?
>
> For 2.6.36 I think you can just use your earlier patch.
>
> Note that on that kernel generic_hdmi_build_pcms() is
> intel_hdmi_build_pcms() in patch_intelhdmi.c.
>
ok
> BTW, I've just been informed by another ATI user that his card was
> actually stereo-only, while he thought earlier it was multichannel
> capable. So, are you sure your card is a multichannel one?
> (if not, it would explain why the card says it is not)
>
> --
> Anssi Hannula
>
Yes, it works fine in Window  so I believe the hardware part is good.