I found the problem: In alsamixer (or kmix, or whatever you use) the "Headphone jack sense" switch must be muted / disabled. Voila -> Sound is back again!
-- No sound on thinkpad T43p in feisty https://launchpad.net/bugs/78299 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs