No 5.1 sound from the internal speakers on Aspire 6930G after upgrade to 12.04 (soundcard Realtek ALC888)

[Alkalyzer]

While my laptop is equipped with an internal 5.1 system (including the "Tuba" subwoofer), only two internal speakers are working after upgrade to 12.04.

I have added these three lines in /etc/pulse/daemon.conf :

default-sample-format = s16le
default-sample-rate = 48000
default-sample-channels = 6

and these two extra lines in /etc/modprobe.d/alsa-base.conf :

alias snd-card-0 snd-hda-intel
options snd-hda-intel model=auto

While these modifications to the original configurations have worked for previous Ubuntu versions (tested on Maverick, Natty, Oneiric), this doesn't seem to work anymore under Precise.

And if the "Sound Settings" menu gives me the option to choose the Analog 5.1 output system, when I test the speakers, only the "Front Right" and "Front Left" tests produce sound.

I have carefully checked that none of the other speakers were muted in alsamixer. The option 6ch in the <Channel> settings of alsamixer was also selected.

In addition, in alsamixer, only the settings "Speaker" and "PCM" have an influence on the output volume and they produce exactly the same effect. Moving the cursors corresponding to "Surround", "Center", "LFE" has absolutely no result.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: alsa-base 1.0.25+dfsg-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic x86_64
NonfreeKernelModules: nvidia
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 2.0.1-0ubuntu7
Architecture: amd64
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC888 Analog [ALC888 Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: lionel 2146 F.... pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf0400000 irq 46'
   Mixer name : 'Nvidia MCP77/78 HDMI'
   Components : 'HDA:10ec0888,1025015e,00100202 HDA:14f12c06,1025015e,00100000 HDA:10de0006,10de0101,00100000'
   Controls : 37
   Simple ctrls : 18
Date: Fri May 18 23:00:07 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:Intel successful
Symptom_Card: Built-in Audio - HDA Intel
Symptom_Jack: Speaker, Internal
Symptom_PulsePlaybackTest: PulseAudio playback test successful
Symptom_Type: Only some of outputs are working
Title: [Aspire 6930G, Realtek ALC888, Speaker, Internal] Playback problem
UpgradeStatus: Upgraded to precise on 2012-04-26 (22 days ago)
dmi.bios.date: 09/12/2008
dmi.bios.vendor: Acer
dmi.bios.version: v0.3121
dmi.board.name: Makalu
dmi.board.vendor: Acer, Inc.
dmi.board.version: Not Applicable
dmi.chassis.type: 1
dmi.chassis.vendor: Acer, Inc.
dmi.chassis.version: N/A
dmi.modalias: dmi:bvnAcer:bvrv0.3121:bd09/12/2008:svnAcer,inc.:pnAspire6930G:pvrNotApplicable:rvnAcer,Inc.:rnMakalu:rvrNotApplicable:cvnAcer,Inc.:ct1:cvrN/A:
dmi.product.name: Aspire 6930G
dmi.product.version: Not Applicable
dmi.sys.vendor: Acer, inc.
mtime.conffile..etc.modprobe.d.alsa.base.conf: 2012-05-18T22:36:10.906528

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

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