Using "laptop-eapd" is the known workaround (and the original "fix" applied in earlier Ubuntu kernels) while upstream addresses the issue.
** Changed in: linux-source-2.6.15 (Ubuntu) Status: Fix Released => Confirmed -- Inaudible sound on Lenovo 3000 N100-07684JU https://launchpad.net/bugs/39517 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs