Update: installing the current mainline kernel (Linux li-MBA 3.2.0-8-generic #15-Ubuntu SMP Wed Jan 11 13:57:44 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux) didn't fix the issue.
Update: installing the current mainline kernel (Linux li-MBA 3.2.0-8-generic #15-Ubuntu SMP Wed Jan 11 13:57:44 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux) didn't fix the issue.