[alsa-devel] ALSA Multichannel through HDMI

John Ettedgui john.ettedgui at gmail.com
Fri Nov 26 07:00:49 CET 2010


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.
>

Too big again :(
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