Recent kernel update caused a regression. sound now not functioning at all.

[brownie17]

Binary package hint: linux-source-2.6.20

after updating to kernel 2.6.20 sound stopped working. all devices are firmly connected, all volumes are unmuted and at full volume, speakers are on, were working fine before update.

the following is the output from the aadebug script.
ALSA Audio Debug v0.1.0 - Sun Aug 5 12:42:35 EST 2007
http://alsa.opensrc.org/aadebug
http://www.gnu.org/licenses/gpl.txt

Kernel ----------------------------------------------------
Linux fraser-desktop 2.6.20-16-generic #2 SMP Thu Jun 7 20:19:32 UTC 2007 i686 GNU/Linux

Loaded Modules --------------------------------------------
snd_cmipci 37024 0
snd_opl3_lib 11520 1 snd_cmipci
snd_hwdep 9988 1 snd_opl3_lib
snd_mpu401_uart 9472 1 snd_cmipci
snd_seq_dummy 4740 0
snd_seq_oss 32896 0
snd_seq_midi 9600 0
snd_rawmidi 25472 2 snd_mpu401_uart,snd_seq_midi
snd_seq_midi_event 8448 2 snd_seq_oss,snd_seq_midi
snd_intel8x0 34332 1
snd_ac97_codec 98464 1 snd_intel8x0
snd_pcm_oss 44544 0
snd_mixer_oss 17408 1 snd_pcm_oss
snd_seq 52592 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event
snd_seq_device 9100 6 snd_opl3_lib,snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq
snd_pcm 79876 4 snd_cmipci,snd_intel8x0,snd_ac97_codec,snd_pcm_oss
snd_timer 23684 3 snd_opl3_lib,snd_seq,snd_pcm
snd 54020 16 snd_cmipci,snd_opl3_lib,snd_hwdep,snd_mpu401_uart,snd_seq_oss,snd_rawmidi,snd_intel8x0,snd_ac97_codec,snd_pcm_oss,snd_mixer_oss,snd_seq,snd_seq_device,snd_pcm,snd_timer
snd_page_alloc 10888 2 snd_intel8x0,snd_pcm

Modprobe Conf ---------------------------------------------
Warning: module config file does not exist
This means any kernel modules will not be auto loaded
See your linux distro docs on how to create this file

Proc Asound -----------------------------------------------
Advanced Linux Sound Architecture Driver Version 1.0.14rc1 (Tue Jan 09 09:56:17 2007 UTC).
 0 [SI7012 ]: ICH - SiS SI7012
                      SiS SI7012 with AD1980 at 0x9400, irq 18
 1 [CMI8738MC6 ]: CMI8738-MC6 - C-Media PCI CMI8738-MC6
                      C-Media PCI CMI8738-MC6 (model 55) at 0x8400, irq 22
  2: : timer
  3: : sequencer
  4: [ 0- 1]: digital audio capture
  5: [ 0- 0]: digital audio playback
  6: [ 0- 0]: digital audio capture
  7: [ 0] : control
  8: [ 1- 0]: raw midi
  9: [ 1- 2]: digital audio playback
 10: [ 1- 2]: digital audio capture
 11: [ 1- 1]: digital audio playback
 12: [ 1- 0]: digital audio playback
 13: [ 1- 0]: digital audio capture
 14: [ 1- 0]: hardware dependent
 15: [ 1] : control
01-00: OPL3 FM
00-01: Intel ICH - MIC ADC : SiS SI7012 - MIC ADC : capture 1
00-00: Intel ICH : SiS SI7012 : playback 1 : capture 1
01-02: CMI8738-MC6 : C-Media PCI IEC958 : playback 1 : capture 1
01-01: CMI8738-MC6 : C-Media PCI 2nd DAC : playback 1
01-00: CMI8738-MC6 : C-Media PCI DAC/ADC : playback 1 : capture 1
Client info
  cur clients : 4
  peak clients : 4
  max clients : 192

Client 0 : "System" [Kernel]
  Port 0 : "Timer" (Rwe-)
  Port 1 : "Announce" (R-e-)
    Connecting To: 15:0
Client 14 : "Midi Through" [Kernel]
  Port 0 : "Midi Through Port-0" (RWe-)
Client 15 : "OSS sequencer" [Kernel]
  Port 0 : "Receiver" (-we-)
    Connected From: 0:1
Client 20 : "C-Media PCI CMI8738-MC6" [Kernel]
  Port 0 : "MPU-401 MIDI 1-0" (RWeX)
Client 21 : "OPL3 FM synth" [Kernel]
  Port 0 : "OPL3 FM Port" (-We-)
  Port 1 : "OPL3 OSS Port" (-we-)

Dev Snd ---------------------------------------------------
controlC0 hwC1D0 pcmC0D0c pcmC0D1c pcmC1D0p pcmC1D2c seq
controlC1 midiC1D0 pcmC0D0p pcmC1D0c pcmC1D1p pcmC1D2p timer

CPU -------------------------------------------------------
model name : Intel(R) Celeron(R) CPU 2.40GHz
cpu MHz : 2421.723

RAM -------------------------------------------------------
MemTotal: 775728 kB
SwapTotal: 1686784 kB

Hardware --------------------------------------------------
00:00.0 Host bridge: Silicon Integrated Systems [SiS] 650/M650 Host (rev 80)
00:02.7 Multimedia audio controller: Silicon Integrated Systems [SiS] AC'97 Sound Controller (rev a0)
00:0e.0 Multimedia audio controller: C-Media Electronics Inc CM8738 (rev 10)
00:10.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
00:10.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)

[Brian Murray (brian-murray)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug does not meet the criteria for a stable release update and is being marked as Won't Fix for this particular version of the kernel. You can learn more about the stable release update process at https://wiki.ubuntu.com/StableReleaseUpdates .
However, the issue that you reported is one that should be possible to test with the live environment of the Desktop CD of the development release - Gutsy Gibbon. It would help us greatly if you could test with it so we can work on getting it fixed in the actively developed kernel. You can find out more about the development release at http://www.ubuntu.com/testing/ .
If you do decide to test with the development release of Ubuntu please comment on this bug report and include at least the minimal information requested at http://wiki.ubuntu.com/KernelTeamBugPolicies . Thanks again and we appreciate your help.