[alsa-devel] ALSA Multichannel through HDMI

Fri Nov 26 16:30:07 CET 2010

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