[alsa-devel] ALSA Multichannel through HDMI

Sun Jan 23 00:34:45 CET 2011

On Sun, Dec 5, 2010 at 2:32 PM, John Ettedgui <john.ettedgui at gmail.com>wrote:

>
>
> On Sat, Dec 4, 2010 at 3:58 PM, Anssi Hannula <anssi.hannula at iki.fi>wrote:
>
>> On 27.11.2010 06:53, John Ettedgui wrote:
>> > 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:
>> >>>>>>>>>>>>>>>>
>> >>>>>>>>>>>>>>>> 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.
>>
>> Did you have a chance to try that?
>>
>> There's no hurry, just making sure I didn't miss any message from you or
>> something :)
>>
>> --
>> Anssi Hannula
>>
>
> I finally tested it.
> Results are soso:
>
>
> -ALSA does not complain anymore about slave.channels 6
> -speaker-test does not complain anymore about -c6
> -my receiver sees the stream as multi channel pcm, not stereo anymore
> -but whatever I try with the ttable config, I can only get sound through
> the left and right speakers.
>
> Hey Anssi,

I will unsubscribe from the alsa-dev mailing list because it is not really
suited for me, but if you have any other idea or want to test anything, feel
free to email me.

Thanks,
John