Intel HDA digital out distortion

Intel HDA digital out distortion

[Ingmar Stieger]

Hi,

a couple of weeks ago, I bought an ASUS mainboard with integrated Intel HDA and 
an AD1988B codec. Unfortunately, the digital / SPDIF output gets distorted with 
stock 1.0.14 drivers. It does not matter what the volume levels of the various 
mixers are set to.

I think I might have found the source for this problem. Maybe it's only a 
workaround, but it solved the issue and digital out now works fine for me, so I 
thought I'd share.

In patch_analog.c, in static struct hda_verb ad1988_spdif_init_verbs[], 
changeing the forth entry

from {0x1d, AC_VERB_SET_AMP_GAIN_MUTE, AMP_IN_UNMUTE(1)},

to {0x1d, AC_VERB_SET_AMP_GAIN_MUTE, AMP_IN_MUTE(1)}

mutes what might be an feedback loop from the analog inputs. The distortion is 
gone if the input to this widget is muted.

On a side note, the settings for the ADCs with NID:08, 09, and 0F looks fishy, 
too. According to the functional diagram, those should have no amps, and thus 
should not be muteable. The driver mutes them anyway...

I'd like to help somebody who really understands this stuff to solve the 
problem for good. What would the next step be ?

Thanks,
Ingmar

Re: Intel HDA digital out distortion

[Matthias Dahl]

Hi Ingmar.

On Monday 23 July 2007 23:09:24 Ingmar Stieger wrote:

> a couple of weeks ago, I bought an ASUS mainboard with integrated Intel HDA
> and an AD1988B codec. Unfortunately, the digital / SPDIF output gets
> distorted with stock 1.0.14 drivers. It does not matter what the volume
> levels of the various mixers are set to.

That makes two of us. I've reported similar problems a few weeks back. So the 
thread "snd-hda-intel, AD 1988b: SPDIF output not working correctly, volume 
low for analog output" maybe of interest to you too. (I posted a similar 
patch just a few minutes before your's by the way -g-)

Could you please tell me what board you have...? If you play back analog sound 
through spdif, do you hear "distortions" in the background like bass-like low 
frequency pumping and so on...?

Best regards,
Matthias Dahl

Re: Intel HDA digital out distortion

[Ingmar Stieger]

Hi Matthias,

Matthias Dahl wrote:

> That makes two of us. I've reported similar problems a few weeks back. So the 
> thread "snd-hda-intel, AD 1988b: SPDIF output not working correctly, volume 
> low for analog output" maybe of interest to you too. (I posted a similar 
> patch just a few minutes before your's by the way -g-)

I've read through your thread, and I think we might have two seperate problems
with this chip ? I am not getting any noise over SPDIF when no sound is
playing, but it will inevitably be distorted at any volume level and mixer
settings if sound is played through aplay or mplayer. I have not tried with
dts, only with wave files, by the way.

Looking at the functional diagram, and trying to mute the various amps that
might have something to do with this, then led to the 0x1D one that I mentioned.

Analog out seems to be fine with the stock drivers for me, altough I did not
compare the volume level with the levels of a Windows driver. At least it is as
loud as my CD player, so I'd say it is ok. It also sounds clean with the stock
drivers. No problem here.

> Could you please tell me what board you have...? If you play back analog sound 
> through spdif, do you hear "distortions" in the background like bass-like low 
> frequency pumping and so on...?

The board came pre-installed in a bare-bone system, so I only know that it is
from ASUS and whatever mainboard they put into their Pundit P2 system. The
chipset is a Intel 945G with ICH7.

I can not discern any special background noise, since the distortion is so loud
that any background noise that might be there is not audible.

Bye,
Ingmar

Intel HDA digital out distortion

[pr0t0cod7]

Hi,

On Monday 23 July 2007 23:09:24 Ingmar Stieger wrote:

> a couple of weeks ago, I bought an ASUS mainboard with integrated
> Intel
> HDA and an AD1988B codec. Unfortunately, the digital / SPDIF output
> gets distorted with stock 1.0.14 drivers. It does not matter what the
> volume levels of the various mixers are set to.

I have the same issues.

Any sound is distorted through spdif output (seems more pronounced with
low frequencies.)

Sound is not distorted:
 - using passthough (playing AC3)
 - when volume is set to the very minimal (no perceptible distortion)
 - with analog output

My motherboard: ASUS P5B deluxe with integrated soundchip
Kernel: 2.6.22
Alsa: Intel HD audio kernel built module
asound.conf: http://pastebin.com/f2c54b47b

> I think I might have found the source for this problem. Maybe it's
> only a workaround, but it solved the issue and digital out now works
> fine for me, so I thought I'd share.

The patch worked for me, no more distortion :)
Thanks for sharing,
Alex.

Re: Intel HDA digital out distortion

[Takashi Iwai]

At Wed, 3 Oct 2007 22:18:46 +0200,
pr0t0cod7 wrote:
> 
> Hi,
> 
> On Monday 23 July 2007 23:09:24 Ingmar Stieger wrote:
> 
> > a couple of weeks ago, I bought an ASUS mainboard with integrated
> > Intel
> > HDA and an AD1988B codec. Unfortunately, the digital / SPDIF output
> > gets distorted with stock 1.0.14 drivers. It does not matter what the
> > volume levels of the various mixers are set to.
> 
> I have the same issues.
> 
> Any sound is distorted through spdif output (seems more pronounced with
> low frequencies.)
> 
> Sound is not distorted:
>  - using passthough (playing AC3)
>  - when volume is set to the very minimal (no perceptible distortion)
>  - with analog output
> 
> My motherboard: ASUS P5B deluxe with integrated soundchip
> Kernel: 2.6.22
> Alsa: Intel HD audio kernel built module
> asound.conf: http://pastebin.com/f2c54b47b
> 
> > I think I might have found the source for this problem. Maybe it's
> > only a workaround, but it solved the issue and digital out now works
> > fine for me, so I thought I'd share.
> 
> The patch worked for me, no more distortion :)
> Thanks for sharing,
> Alex.

Could you check whether the problem got fixed with ALSA 1.0.15rc3?


thanks,

Takashi

Re: Intel HDA digital out distortion

[pr0t0cod7]

Le Tue, 09 Oct 2007 11:49:30 +0200,
Takashi Iwai <tiwai@suse.de> a écrit :

> At Wed, 3 Oct 2007 22:18:46 +0200,
> pr0t0cod7 wrote:
> > 
> > Hi,
> > 
> > On Monday 23 July 2007 23:09:24 Ingmar Stieger wrote:
> > 
> > > a couple of weeks ago, I bought an ASUS mainboard with integrated
> > > Intel
> > > HDA and an AD1988B codec. Unfortunately, the digital / SPDIF
> > > output gets distorted with stock 1.0.14 drivers. It does not
> > > matter what the volume levels of the various mixers are set to.
> > 
> > I have the same issues.
> > 
> > Any sound is distorted through spdif output (seems more pronounced
> > with low frequencies.)
> > 
> > Sound is not distorted:
> >  - using passthough (playing AC3)
> >  - when volume is set to the very minimal (no perceptible
> > distortion)
> >  - with analog output
> > 
> > My motherboard: ASUS P5B deluxe with integrated soundchip
> > Kernel: 2.6.22
> > Alsa: Intel HD audio kernel built module
> > asound.conf: http://pastebin.com/f2c54b47b
> > 
> > > I think I might have found the source for this problem. Maybe it's
> > > only a workaround, but it solved the issue and digital out now
> > > works fine for me, so I thought I'd share.
> > 
> > The patch worked for me, no more distortion :)
> > Thanks for sharing,
> > Alex.
> 
> Could you check whether the problem got fixed with ALSA 1.0.15rc3?
> 
> 
> thanks,
> 
> Takashi

Works perfect with 1.0.15rc3.

Thanks,
Alex.
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