[alsa-devel] ALSA Multichannel through HDMI

Fri Nov 26 06:56:35 CET 2010

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.
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