No sound after kernel 3.2 and general update 22 June 2012

[peter_pclos]

After upgrading to Kernel version 3.2.18-pclos2.bfs and then carrying out the general upgrade of about 80 or so packages indicated on Synaptic, sound output was reduced to the merest whisper, despite all user-defined settings being 100%.  Using alsaconf as recommended elsewhere in the Forum gives a temporary fix, but it doesn't survive a re-start of the system.  Elsewhere in the Forum (now in 'Tips and Tricks') another solution was suggested using the KMix settings to retrieve a Speaker channel.  However, on exploring KMix I find the following possibilities in my system:

Visible channels:  Master, PCM, Headphone, Digital, Line

Available channels: Capture 2, Input source, Capture, Input Source 2, Rear Mic, Rear Mic Boost, Front, Surround, Channel Mode, Center, LFE, Auto-Mute Mode

I don't actually identify any of the 'still available' channels as offering me any help.

Has anybody out there any other suggestions?

The sound, using the on-board sound facility on the motherboard (ASUS M5A78L-M LX V2 running with an AMD Athlon II X2 250 processor and 4GB RAM) was perfectly OK prior to the 22nd June upgrades (which must have included KDE changes, since I lost all my wallpapers at the same time!)

[Old-Polack]

peter_pclos:

Did you try to restore your previous settings yet?

http://www.pclinuxos.com/forum/index.php/topic,106364.msg908596.html#msg908596

[peter_pclos]

Thanks Old-Polack.  Yes, I've now done that.  My original KDE desktop settings came back, but the situation re sound is unchanged.  alsaconf still produces only a temporary fix, destroyed both by restart and logout/login, and the position on KMix Settings is only different in that Front Mic and Rear Mic Boost are now in the 'available' list, which isn't much help as far as output is concerned!

If it's not simply naive to think of making the alsaconf fix permanent, how do I set about it?

[Old-Polack]

Thanks Old-Polack.  Yes, I've now done that.  My original KDE desktop settings came back, but the situation re sound is unchanged.  alsaconf still produces only a temporary fix, destroyed both by restart and logout/login, and the position on KMix Settings is only different in that Front Mic and Rear Mic Boost are now in the 'available' list, which isn't much help as far as output is concerned!

If it's not simply naive to think of making the alsaconf fix permanent, how do I set about it?

I really don't know. When I run alsaconf, the settings always stick without having to do anything else. 

[peter_pclos]

Well, that's a bit of a problem,  isn't it!  As far as I can see the basic hardware configuration is OK, with the Control Center reporting:

Your card currently use the ALSA "snd_hda_intel" driver (default driver for your card is "snd_hda_intel")

which (give or take a grammatical quibble) would seem to confirm that the correct driver is in place.  The only inconsistency from following through the Control Center/Sound Card/Advanced/Trouble Shooting tests is that when I tried to use "aumix -q" I got the error message "aumix: command not found".  However, Synaptic tells me that what I've got installed is aumix-text, and when I run "aumix-text -q" I get:

[my_ID@localhost ~]$ aumix-text -q
vol 70, 70
line 0, 0
pcm2 0, 0
igain 0, 0
dig1 100, 100
[my_ID@localhost ~]$

which is odd, because KMix tells me I have PCM at 100%, not PCM2 at 0%.  and "igain" in the aumix-text result doesn't appear to correspond to anything in the KMix settings, and stays stubbornly at 0% whatever I do.  However, having run alsaconf from this position, and with only Master and PCM set to 100% in KMix, I get sound from my speakers, and the aumix-text output in this state is:

[my_ID@localhost ~]$ aumix-text -q
vol 100, 100
line 0, 0
pcm2 0, 0
igain 0, 0
dig1 100, 100
[my_ID@localhost ~]$

which if 'vol' is interpreted as 'Master' and 'dig1' as PCM, makes some sort of sense.  What doesn't seem to make much sense, of course, is that this is exactly the same pattern of settings as those given (see first quote) when the alsaconf effect had been lost after a re-boot.

I intended this response as clarification; whether it has clarified anything is a moot point, but I'm open to further comments.  BTW, where is the data stored which alsaconf modifies?

[Just17]

You might wish to have a look at Qas mixer .......  it has more than anyone would ever need to know about the audio devices 

Some have found it useful in such situations.

[peter_pclos]

Experimenting with various mixers didn't improve the result.  However, in the clearer light of day, I re-visited my former scientific background and ran a control experiment, by booting up with the previous version of the kernel, 2.6.38.8-pclos3.bfs.  This produced completely normal sound performance, so I assume as a working hypothesis that there is some problem with the interaction between alsa and the 3.2.18-pclos2.bfs kernel.  Can anyone with a better understanding of systems suggest my next move?  Would a re-install of alsa in the 3.2.18-pclos2.bfs environment be likely to succeed, and if so, should it actually be a complete removal followed by a re-install?  Would the latter involve any risk of removing components vital to other processes?

Just to confirm, I've re-started into the new kernel, and the sound has vanished.

[Just17]

I would be more inclined to boot into the older kernel, uninstall the new one, reboot, reinstall the new kernel again, and immediately reboot into the new kernel.

It would at least eliminate any glitch during the previous installation as the cause.

[deathromantik]

Have you tried changing the ALSA backend?

[peter_pclos]

On a point of clarification, where is the functionality to change the alsa backend?  I don't see it in the Control Center, and alsaconfig doesn't present me with any relevant options.

[deathromantik]

Double click the speaker icon on the taskbar to go to, then Settings>Audio Setup select Audio Output to go to the Phenon - KDE Control Module and then try testing each of the audio devices on the right by selecting them and clicking test.
If this does not work click the Backend tab and move another back end up to the top of the list and click Apply. Then logout and log back in.
If this does not work try installing another Phenon backend in synaptic and configuring it as above.
I hope that this helps.

[Loles]

Check this and see if it helps

http://www.pclinuxos.com/forum/index.php/topic,106900.msg913841.html#msg913841