[ATIIXP - ATI IXP] SPDIF output does not work with pulseaudio (reason included)

[Jason Gunthorpe]

Binary package hint: pulseaudio

SPDIF works fine if pulseaudio is disabled via aplay

The problem is that this ALSA environment has this mixer control:
Simple mixer control 'IEC958 Playback AC97-SPSA',0
  Capabilities: volume volume-joined penum
  Playback channels: Mono
  Capture channels: Mono
  Limits: 0 - 3
  Mono: 3 [100%]

Which pulseaudio *forces* to be '3' and keeps it there. Unfortunately *this is not a volume control* - inside the kernel this setting controls the SPSA channel assignment (see the A97 2.2 spec page 58). For output to work on my system this must be set to 0 - S/PDIF source data assigned to AC-link slots 3&4

I'm not sure who is at fault here. Some possibilities:
 1) The kernel should export this as an ENUM type setting, not a volume slider
 2) pulseaudio should treat it in some special way and at least let me set it to 0
 3) Something else?? What is this even used for? The 'right' setting might naturally fall out depending on the channel count, or hardware config and this shouldn't even leave the kernel at all?

Clearly, at least the current situation is completely useless. The value needs to be set properly, pulse has no way to set it, thus I get no sound.

There have been other bugs related to this.. bug #198523, for instance. It is really obscure that something that looks like a volume slider has nothing to do with volume and is *critical* to proper sound output!!

Jason

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: alsa-base 1.0.23+dfsg-1ubuntu4
ProcVersionSignature: Ubuntu 2.6.35-22.32-generic 2.6.35.4
Uname: Linux 2.6.35-22-generic i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.23.
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: IXP [ATI IXP], device 0: ATI IXP AC97 [ATI IXP AC97]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: jgg 1933 F.... pulseaudio
 /dev/snd/pcmC0D0p: jgg 1933 F...m pulseaudio
Card0.Amixer.info:
 Card hw:0 'IXP'/'ATI IXP rev 2 with ALC658D at 0xfe02a000, irq 17'
   Mixer name : 'Realtek ALC658D'
   Components : 'AC97a:414c4781'
   Controls : 38
   Simple ctrls : 24
Date: Sat Sep 18 23:00:05 2010
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Beta i386 (20100901.1)
PackageArchitecture: all
ProcEnviron:
 LANGUAGE=en
 PATH=(custom, no user)
 LANG=C
 SHELL=/bin/bash
SelectedCard: 0 IXP ATIIXP - ATI IXP
SourcePackage: alsa-driver
Symptom: audio
Title: [ATIIXP - ATI IXP] ALSA test tone not correctly played back
dmi.bios.date: 09/30/2005
dmi.bios.vendor: Phoenix Technologies, LTD
dmi.bios.version: 3.35
dmi.board.name: AMETHYST-M
dmi.board.vendor: MSI
dmi.board.version: 1.0
dmi.chassis.type: 3
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnPhoenixTechnologies,LTD:bvr3.35:bd09/30/2005:svnCompaqPresario061:pnED865AA-ABASR1610NXNA540:pvr0n41411RE101AMETH00:rvnMSI:rnAMETHYST-M:rvr1.0:cvnHewlett-Packard:ct3:cvr:
dmi.product.name: ED865AA-ABA SR1610NX NA540
dmi.product.version: 0n41411RE101AMETH00
dmi.sys.vendor: Compaq Presario 061

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 10.10 (maverick) reached end-of-life on April 10, 2012.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

Please upgrade to the latest version and re-test.

[Launchpad Janitor (janitor)]

[Expired for pulseaudio (Ubuntu) because there has been no activity for 60 days.]