Optical SPDIF nforce4: Light but no sound

[Fre]

I have a MSI K8N Neo4 Platinum Edition mainboard with nforce4 chipset.
The analog audio outputs work fine, with both alsa and nvsound (nvidia's driver which uses oss).

Whatever I try, I can't get the optical SPDIF output to work.
I connect it to my Denon 1804 HT receiver, but hear nothing.
The same optical input on that receiver works perfect with a Sony CD-player from 1991.

As soon as I try to use the optical output (with xine, mplayer, xmms, aplay, mpg123, mp321, ...) the SPDIF's red light goes on until reboot, but nothing is heard. Maybe a problem of rate or volume?

I tried alsamixer, alsamixergui, gnome-alsamixer and kmix to change the volumes and mute - unmute status of each channel.
Alsamixer doesn't allow me to mute the "IEC958 Play AC97.." channel or to change it's 100% volume.
Changing the volume of the "IEC958 P" channel in gnome-alsamixer often results in the following error:
(gnome-alsamixer:6174): Gtk-CRITICAL **: gtk_adjustment_get_value: assertion `GTK_IS_ADJUSTMENT (adjustment)' failed

I tried several .asoundrc files, especially the one from
http://www.gossamer-threads.com/lists/mythtv/users/61265?do=post_view_threaded#61265

Anybody any tips?
Is nforce4 optical SPDIF not supported yet?

Info:

(Debian sarge)

more /dev/sndstat
Sound Driver:3.8.1a-980706 (ALSA v1.0.6 emulation code)
Kernel: Linux mystica 2.6.10-1-386 #1 Tue Jan 18 03:33:26 EST 2005 i686
Config options: 0

Installed drivers:
Type 10: ALSA emulation

Card config:
NVidia CK804 with ALC850 at 0xfebfd000, irq 209

Audio devices:
0: NVidia CK804 (DUPLEX)

Synth devices: NOT ENABLED IN CONFIG

Midi devices: NOT ENABLED IN CONFIG

Timers:
7: system timer

Mixers:
0: Realtek ALC850 rev 0



amixer info
Card default 'CK804'/'NVidia CK804 with ALC850 at 0xfebfd000, irq 209'
Mixer name : 'Realtek ALC850 rev 0'
Components : 'AC97a'
Controls : 42
Simple ctrls : 26

amixer scontrols
Simple mixer control 'Master',0
Simple mixer control 'Master Mono',0
Simple mixer control 'PCM',0
Simple mixer control 'Surround',0
Simple mixer control 'Center',0
Simple mixer control 'LFE',0
Simple mixer control 'Line',0
Simple mixer control 'Line-In As Surround',0
Simple mixer control 'CD',0
Simple mixer control 'Mic',0
Simple mixer control 'Mic As Center/LFE',0
Simple mixer control 'Mic Boost (+20dB)',0
Simple mixer control 'Mic Select',0
Simple mixer control 'Video',0
Simple mixer control 'Phone',0
Simple mixer control 'IEC958',0
Simple mixer control 'IEC958 Input Monitor',0
Simple mixer control 'IEC958 Playback AC97-SPSA',0
Simple mixer control 'PC Speaker',0
Simple mixer control 'Aux',0
Simple mixer control 'Mono Output Select',0
Simple mixer control 'Capture',0
Simple mixer control 'Mix',0
Simple mixer control 'Mix Mono',0
Simple mixer control 'Duplicate Front',0
Simple mixer control 'External Amplifier',0


aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: CK804 [NVidia CK804], device 0: Intel ICH [NVidia CK804]
Subdevices: 1/1
Subdevice #0: subdevice #0
card 0: CK804 [NVidia CK804], device 2: Intel ICH - IEC958 [NVidia CK804 - IEC958]
Subdevices: 1/1
Subdevice #0: subdevice #0

cat /proc/asound/devices
0: [0- 0]: ctl
18: [0- 2]: digital audio playback
25: [0- 1]: digital audio capture
16: [0- 0]: digital audio playback
24: [0- 0]: digital audio capture
1: : sequencer
33: : timer

[Gilly]

will the output have to be 48/44.1Khz? i think my audigy defaults to 96Khz which makes the output un-usable with most things

[Fre]

The sound chip is said to be limited to 48kHz.
The receiver is probably quite flexible.


In the meantime I had a look at the OSD On Screen Display of my receiver. It recognizes the computer connection:

Nothing connected:
SIGNAL : ANALOG

SPDIF computer connected (soundfile playing or not):
SIGNAL : PCM ZERO
fs : 48kHz

OPT OUT CD player connected:
SIGNAL : PCM ZERO
fs : 44.1kHZ

After playing CD for 15s:
SIGNAL : PCM
fs : 44.1kHZ

Also, at almost max volume of the receiver, I can hear sometimes changing the background noise while playing a sound file on the computer with:
mplayer -vo null -ac hwac3 TestAC3.avi

So, both tests make me think that the signal is played correctly, but that the sound stays muted or at volume zero, no matter what I change in the many mixers I tried...

Somebody any idea now?

[Gilly]

is bitsteam out turned on? because it is getting some form of signal but i dont know if it knows what to do with it

[Fre]

Where should I enable what exactly and how?

Thx

[Gilly]

no idea but i know that some DVD players need to have PCM out enabled if they are to work in 5.1, some internally decode and others need bit stream out. Not sure what all these things mean though

[tac]

Hi,

I have an asus a8n-sli mb, I tried to use spdif rca digital output (coaxial). And I have no sound, like you.

My old mb was an asus a7n8x and the spdif rca digital output works fine with the last nvidia drivers (1.0-0301).

Perhaps it's a drivers problem, or a nforce 4 incompatibility...
I tried with alsa too...

T++

P.S. here http://www.nvnews.net/vbulletin/showthread.php?t=47989 I ask for help...

[eklarson]

I'm having the same problems.

Followed the instructions on http://alsa.opensrc.org/index.php?page=DigitalOut with no luck.

[eklarson]

I've created a bug report on the ALSA bugtracking system. Its number is 0001094 - "nforce4 - optical spdif out not working". If you are having this same problem please go to https://bugtrack.alsa-project.org/alsa-bug/login_page.php and report it.

[pzgren]

Hello,

has anybody tried with ALSA for digital output this option for the oss emulation in the /etc/modprobe.conf:

options snd-pcm-oss dsp_map=2 adsp_map=2

And this /etc/asound.conf or $HOME/.asoundrc: