[alsa-devel] snd-hda-intel, AD 1988b: SPDIF output not working correctly, volume low for analog output

Takashi Iwai tiwai at suse.de
Tue Jul 17 12:21:25 CEST 2007

At Tue, 17 Jul 2007 08:32:00 +0200,
Matthias Dahl wrote:
> Hello everyone.
> I very recently upgraded my system to a Asus Crosshair (AM2, nforce 590 sli) 
> board because it seemed just good quality. Unfortunately the AD1988b chip on 
> it is causing me some trouble.
> 1] SPDIF output 
> When I use it for dts/dolby passthrough, it works just fine even though from 
> time to time spdif just hangs- not during playback but when I start the 
> playback. (analog output is unaffected) Meaning that either the player is 
> hanging or playback starts but I hear no sound. After that only a reboot 
> solves the problem... restarting alsa has not effect.
> Also when the passthrough stops or during playback of anything else besides a 
> dts/dolby stream, I hear a low pitch beating (usually in combination with a 
> very high pitch sound) in the background.
> I double checked everything to be sure that my other equipment was fine and 
> not the cause of this.

Which applications are you using? 

For further analysis, first get /proc/asound/card0/codec#* files for
both working and non-working states.  This includes most of codec
register information, so we can compare the details.  In addition, run
"alsactl -f somefile store" in both cases, too.  This file contains
the mixer status.

Also, check the kernel messages when it hangs.  If it's related to the
controller communication error, it must show some timeout messages.

> 2] analog output
> I am unable to get it as loud as with the win drivers without overdriving it. 
> The volume is okay... but not on par with the win drivers. That's especially 
> true for the SPDIF output. Increasing the SPDIF volume usually results in 
> worse audio quality over spdif and increased "noise" (see above).
> Like said earlier, I checked with the win drivers, and everything (audio wise) 
> works just fine there. So it's not a hardware fault. (relief -g-)
> My guess would be that the AD 1988b is quite a bit different to program from 
> its 1988 predecessors as it contains dts live and stuff. Just a guess...

No, it's almost same (if we rely on the datasheet).

Did you try any model module option?  It might be a BIOS problem that
doesn't set up the codec informatoin correctly.  With model option, we
can override and use the preset configuration.


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