The same thing happens on macbooks that uses the Audio Chip 82801G. I can hear some noise when enabling che micophone but nothing coming from the mic.
Also other friend of mine with macbook has the same problem. Maybe someone should change the title to a generic snd-hda-intel bug -- microphone not working on Amilo Si with snd-hda-intel https://launchpad.net/bugs/63401 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs