Comment 3 for bug 152142

I had this problem using a lenovo 3000 v200 laptop.

Everything seems to be ok (lsmod ok, xmms playing ok) but no sound. After severals configurations and google research I found this links
https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/108392 and in particular this post
"
 esperanc wrote on 2007-05-16: (permalink)

I just figured out a procedure to make the sound work again in my hp laptop. Usually, I use the laptop connected to the power source. If I shut down, disconnect the power and boot using the battery, Feisty comes up with sound again. I also verified that booting Vista (on my dual boot laptop) kills the sound after I reboot with Linux. Apparently, the bug does have something to do with ACPI.
"

So, I tried to boot my laptop on battery, and "oh miracle" the sound works fine. I put the AC current back and the sound was still there.

But another bug appears : putting headphones does not shut down speackers !!! a known bug
https://bugs.edge.launchpad.net/ubuntu/+source/linux-source-2.6.22/+bug/94566

Hope this helps

Yann