[ALSA - driver 0001083]: NVIDIA CK8 ALC655 SPDIF passthrough

[bugtrack@alsa-project.org]

A NOTE has been added to this issue.
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<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=1083> 
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Reported By:                vedran
Assigned To:                
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Project:                    ALSA - driver
Issue ID:                   1083
Category:                   PCI - intel8x0
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     new
Distribution:               Debian sid
Kernel Version:             2.6.10-ac12
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Date Submitted:             04-29-2005 15:33 CEST
Last Modified:              06-08-2005 15:01 CEST
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Summary:                    NVIDIA CK8 ALC655 SPDIF passthrough
Description: 
We're using a motherboard with nVidia nforce2IGP chipset, and the sound
device on this board is NVidia CK8, Realtek ALC655 rev 0. The motherboard
is MSI K7N2GM2, and SPDIF passthrough works fine on Windows XP with stock
realtek drivers.

On Linux, I'm using the latest ALSA CVS (29.04.2005.) on a 2.6.10-ac12
kernel.

I've been able to make a 2 channel  pre-decoded SPDIF output work by using
the hw:0,2 device. If I use the default device, there is no sound on
SPDIF, regardless of the SPDIF related controls in mixer. The controls in
the mixer are:

However, I'm having trouble with AC3 passthrough, I'm using ac3dec -C from
alsa-tools CVS, and I get no sound.

I'm attaching the archive with the output of iecset and
/proc/asound/card0/codec97#0/* files during the ac3dec run, and when
idle.

Maybe the fact that decoded SPDIF output is not working until I pass it
through the hw:0,2 has something to do with this, how can I make ac3dec -C
use hw:0,2?
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Relationships       ID      Summary
----------------------------------------------------------------------
has duplicate       0001094 nforce4 - optical spdif out not working
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 Human - 06-06-05 23:30 
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I wanted to add that SPDIF works on nForce4 using ALSA 1.0.6.  Apparently,
there has been a regression on nForce4 between 1.0.6 and 1.0.9/1.0.9a. 
Here are the steps I took to verify that it worked.  You may just need to
install ALSA 1.0.6 to test it, but here's everything I did.

1) Install KnoppMyth R5A12 (which includes ALSA 1.0.6).
2) connect your nForce4 motherboard's coaxial S/PDIF output to your
receiver's coaxial digital audio in connector
3) run xine and configure audio for Pass Through
4) using xine, play a ripped DVD with an AC3 soundtrack

This works with the Gigabyte GA-K8NF-9 and the MSI K8N Neo4 Platinum. 
What other information can I provide in order to get nForce4 working again
in ALSA?

----------------------------------------------------------------------
 tiwai - 06-08-05 15:01 
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Interesting.  First of all, the SPDIF support on nForce is partial, AFAIK. 
Since the SPDIF status bits are not set up correctly on nForce, many
digital receivers can't accept the AC3 signals.  But the PCM over SPDIF
seems working.  This was the last state I tested (quite ago).

Now, you reported that there is a regression in another point.  OK, this
has to be fixed.  Could you elaborate what did you downgrade?  The
combination of 1.0.6 driver + 1.0.9 lib works, or vice versa?

For checking, use ac3dec (with -C option) in alsa-utils to reduce other
unknown factors.

If the above combinations don't work, get /proc/asound/card0/codec97#0/*
(might be a different directory name in 1.0.6) _during_ ac3 playback on
1.0.6 and 1.0.9 environment to compare.

Issue History
Date Modified  Username       Field                    Change              
======================================================================
04-29-05 15:33 vedran         New Issue                                    
04-29-05 15:33 vedran         File Added: spdif_passthrough.tar.gz              
     
04-29-05 15:33 vedran         Distribution              => Debian sid      
04-29-05 15:33 vedran         Kernel Version            => 2.6.10-ac12     
05-30-05 13:21 vedran         Note Added: 0004809                          
06-01-05 16:53 tiwai          Note Added: 0004862                          
06-01-05 16:54 tiwai          Relationship added       has duplicate 0001094
06-01-05 19:19 eklarson       Issue Monitored: eklarson                    
06-03-05 00:31 Human          Note Added: 0004880                          
06-03-05 00:32 Human          Issue Monitored: Human                       
06-06-05 23:30 Human          Note Added: 0004910                          
06-08-05 15:01 tiwai          Note Added: 0004928                          
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