[alsa-devel] ALSA Multichannel through HDMI

Sat Nov 27 05:53:58 CET 2010

On Fri, Nov 26, 2010 at 7:30 AM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
> On 26.11.2010 08:00, John Ettedgui wrote:
>> On Thu, Nov 25, 2010 at 9:56 PM, John Ettedgui <john.ettedgui at gmail.com> wrote:
>>> On Thu, Nov 25, 2010 at 6:21 PM, John Ettedgui <john.ettedgui at gmail.com> wrote:
>>>> On Thu, Nov 25, 2010 at 6:16 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>> On 26.11.2010 04:02, John Ettedgui wrote:
>>>>>> On Thu, Nov 25, 2010 at 5:08 PM, John Ettedgui <john.ettedgui at gmail.com> wrote:
>>>>>>> On Thu, Nov 25, 2010 at 4:59 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>>>>> On 26.11.2010 02:53, John Ettedgui wrote:
>>>>>>>>> On Thu, Nov 25, 2010 at 3:34 PM, John Ettedgui <john.ettedgui at gmail.com> wrote:
>>>>>>>>>> On Thu, Nov 25, 2010 at 3:15 PM, Anssi Hannula <anssi.hannula at iki.fi> wrote:
>>>>>>>>>>> On 26.11.2010 01:11, John Ettedgui wrote:
>>>>>>>>>>>> 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.
>>>>>>>>>>>
>>>>>>>>>>> And you are sure it is multichannel PCM, and not e.g. multichannel DTS
>>>>>>>>>>> or multichannel AC-3 with on-the-fly compression, which are possible
>>>>>>>>>>> with stereo hdmi as well?
>>>>>>>>>>>
>>>>>>>>>>> Just making sure :)
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Anssi Hannula
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Well, I have not super tested it, but the reason I believe it is is
>>>>>>>>>> simple, when I use passthrough my receiver says Dolby digital or
>>>>>>>>>> something like that, but in Windows just going around or playing games
>>>>>>>>>> it says Multichannel.
>>>>>>>>
>>>>>>>> Sounds ok then.
>>>>>>>>
>>>>>>>>>> I'll get the patch applied in a few minutes, I was running out of
>>>>>>>>>> memory and my system was getting really slow... :)
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I am not sure if I did it right but now I don't even get hdmi sound
>>>>>>>>> working anymore.
>>>>>>>>> It is not listed in aplay-l, and dmesg gives me this:
>>>>>>>>> [drm:radeon_dvi_detect] *ERROR* HDMI Type A-1: probed a monitor but
>>>>>>>>> no|invalid EDID
>>>>>>>>>
>>>>>>>>> I've attached the patch I used, since I could not used the previous
>>>>>>>>> one I had to hack it, maybe I broke something?
>>>>>>>>> (I have not set channels to 8 yet, just changed the parser)
>>>>>>>>
>>>>>>>> The patch looks ok. The above error message is weird, as it comes from
>>>>>>>> the display driver which should not be affected by the patch at all.
>>>>>>>>
>>>>>>>> I'll look at the code later (tomorrow maybe). Until then I'd advise you
>>>>>>>> to retry without the patch and with the patch again, just to make sure
>>>>>>>> this is not some unrelated issue...
>>>>>>>> Also, post the whole dmesg when it works (2 channel, without patch), and
>>>>>>>> when it doesn't (with patch).
>>>>>>>>
>>>>>>>> --
>>>>>>>> Anssi Hannula
>>>>>>>>
>>>>>>> Following your message I restarted my computer and that error was
>>>>>>> gone, yet there is still nothing display in aplay -l / aplay -L about
>>>>>>> hdmi anymore.
>>>>>>> I'll go back to my non patched kernel and see what it does.
>>>>>>>
>>>>>> With the non-patched kernel I get back my hdmi in aplay -l, so it
>>>>>> looks like the patch messed up something.
>>>>>
>>>>> Indeed.
>>>>>
>>>>>> I really think that when I tried it before it did not do that, but it
>>>>>> was so long ago that I could be wrong...
>>>>>
>>>>> Well, the driver has changed since then, it could be more strict now :)
>>>>>
>>>>>> Anyway here are the 2 dmesgs (not sure if they'll help though).
>>>>>
>>>>> Indeed, there doesn't seem to be any difference. Maybe try with
>>>>> CONFIG_SND_DEBUG_VERBOSE?
>>>>>
>>>>> --
>>>>> Anssi Hannula
>>>>>
>>>>
>>>> Sure I'll get that.
>>>>
>>>
>>> There you go.
>
>> ALSA sound/pci/hda/hda_intel.c:2531: chipset global capabilities = 0x1001
>> ALSA sound/pci/hda/hda_intel.c:913: codec_mask = 0x1
>> ALSA sound/pci/hda/hda_intel.c:1354: codec #0 probed OK
>> ALSA sound/pci/hda/hda_generic.c:683: hda_generic: no proper input path found
>
> Hm, for some reason it doesn't try to use the intelhdmi module. Is it
> getting loaded? Have you run "depmod"?
> Does "modinfo snd-hda-codec-intelhdmi" show the alias you added?
>
> --
> Anssi Hannula
>

I'm sorry it's my fault.
I did not realize my patch was buggy, I had a white line and because
of it the last part of the patch did not get applied.

Now aplay -l is fine, and I can use the hdmi again, but still it
defaults to stereo.
With a "default" asound.conf speaker-test won't allow for more than -c2.
I tried to add channels 6 in the conf file, but it made no difference...

I will try your other suggestion.

Thanks,
John