[alsa-devel] PROBLEM: snd_intel_hda audio regression in 2.6.36-rc5

[Takashi Iwai]

At Wed, 22 Sep 2010 17:28:15 +0300,
Aki Parviainen wrote:
> 
> On Wed, Sep 22, 2010 at 12:31 PM, Takashi Iwai <tiwai at suse.de> wrote:
> 
> > At Tue, 21 Sep 2010 20:32:54 +0300,
> > Aki Parviainen wrote:
> > >
> > > I've noticed an audio related problem in 2.6.36-rc5: when using
> > 2.6.36-rc5 kernel
> > > I don't get normal two channel PCM audio at all on my machine, however
> > multichannel audio
> > > works just fine.
> >
> > What does this mean exactly?  Could you show your test method?
> >
> >
> Thank you for your answer and sorry for being unclear! This means that
> whenever I try to output regular stereo audio from files or DVB for example
> I cannot hear anything at all with 2.6.36-rcX kernels. Before 2.6.36-rcX
> kernels normal stereo audio works just fine. However with 2.6.36-rcX kernels
> and all the previous kernels digital preencoded (like Dolby Digital, DTS)
> audio works just fine. I am using Kaffeine 1.0 and VLC 1.1 (both from Debian
> unstable) to play audio, both programs work exactly the same. My test method
> is basicly this:
> -boot with 2.6.36-rc4 or 2.6.36-rc5
> -open kaffeine or vlc
> -start playing mp3 file -> nothing comes to the amplifier
> -start playing mkv file with 5.1 track -> correct audio comes to the
> amplifier

So, you are testing only over SPDIF output, right?

> > > I'm using snd_hda_intel and I've configured ALSA to send all
> > > audio to spdif output. With earlier kernel versions this kind of setup
> > works
> > > just fine but with 2.6.36-rc5 only audio that works is digital preencoded
> > audio (5.1 dolby digital from
> > > dvd:s / mkv:s) works. There's no errors or anything but nothing comes to
> > my
> > > amplifier. I've also tested 2.6.36-rc4 and it has the same problem, in
> > the past I've never had any audio problems with mainline kernels.
> >
> > Which kernel did it work?
> >
> 
> 2.6.35.5 and every earlier kernel tested. Unfortunately the first 2.6.36
> based kernel that I tested was 2.6.36-rc4 and there audio doesn't work
> anymore.
> 
> 
> >
> > > Booting with earlier kernel solves the problem immediately.
> >
> > Run alsa-info.sh (with --no-upload option) on both working and
> > non-working kernel, and attach two files for compare.  This will give
> > a more clear sight what is different between them.
> >
> >
> Here's the alsa-info files attached from 2.6.35.5 (works) and 2.6.36-rc5
> (doesn't work).

Looks like the SPDIF status bits has been reset by some reason.
Try to restore via iecset program included in alsa-utils package,
e.g.
    iecset original on
    iecset category 0x02

If this doesn't help, try to unload sound driver once, remove (or
backup) /etc/asound.state (which might be in a different path
depending on the distro), then load sound modules again.
This will restore the default SPDIF status.  Unmute / adjust mixer
setups appropriately after doing this.


Takashi