Bug 11419

Summary:	No sound output with cmipci on SP/DIF
Product:	Drivers	Reporter:	Moritz Mühlenhoff (jmm)
Component:	Sound(ALSA)	Assignee:	Jaroslav Kysela (perex)
Status:	REJECTED INVALID
Severity:	normal	CC:	clemens
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.26	Subsystem:
Regression:	Yes	Bisected commit-id:

Description Moritz Mühlenhoff 2008-08-24 13:57:21 UTC

Latest working kernel version: 2.6.18 (maybe later ones as well)
Earliest failing kernel version: 2.6.25
Distribution: Debian
Hardware Environment: C-Media CMI8738
Software Environment: Debian Lenny
Problem Description:

I've upgraded my system from Debian Etch with a 2.6.18 kernel to the current pre-release version of Debian Lenny and I no longer have sound output on SP/DIF.

I've tested 2.6.25 and 2.6.26 kernels. All media players seem to process the audio just fine. If I boot the 2.6.18 kernel sound output works fine again.

Steps to reproduce: Play any sound file.

I'm attaching the output of /proc/asound/DEVICE/cmipci as advised in the ALSA wiki:

2.6.18:
C-Media PCI CMI8738-MC6 (model 55) at 0xd800, irq 11

00: 02 00 01 00
04: 50 1d 00 00
08: 03 00 09 00
0c: 00 00 01 08
10: c0 00 00 00
14: 00 00 80 00
18: 00 80 80 0c
1c: 00 00 fe ff
20: 10 40 08 00
24: 00 01 00 00
28: ff ff ff ff
2c: ff ff ff ff
30: 00 00 00 00
34: 00 00 00 00
38: 00 00 00 00
3c: 00 00 00 00

C-Media CMI8738 (model 55) at 0xd800, irq 11

00: 02 00 01 00
04: 10 1c 00 00
08: 03 00 09 00
0c: 00 00 01 08
10: c0 00 00 00
14: 00 00 00 00
18: 00 80 80 0c
1c: 00 00 fe ff
20: 10 40 08 00
24: 00 01 00 04
90: 20 09 00 00

Please let me know if you need further information.

Comment 1 Clemens Ladisch 2008-08-26 23:59:21 UTC

The registers indicate that the driver did not enable the S/PDIF output because it was not told to do so.

Try enabling the "IEC598 Output Switch" mixer control.

Apparently, the new Debian does not read the saved mixer configuration of the old one.

Comment 2 Moritz Mühlenhoff 2008-08-28 14:04:52 UTC

(In reply to comment #1)
> The registers indicate that the driver did not enable the S/PDIF output
> because
> it was not told to do so.
> 
> Try enabling the "IEC598 Output Switch" mixer control.
> 
> Apparently, the new Debian does not read the saved mixer configuration of the
> old one.

Thanks for your help, that was indeed the issue. IEC598 didn't exactly catch my attention as an option for SP/DIF output.