Fairly certain that this is because of the atheros crash in your dmesg. When that gets fixed, your sound will likely work too.
** Changed in: linux-source-2.6.20 (Ubuntu) Status: Needs Info => Rejected -- 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