Same issue. Ubuntuforums has all of the information that I gathered about it, including possibly a problem with the Alsa driver not correctly recognizing the hardware in the first place.
http://ubuntuforums.org/showthread.php?t=784597 -- Microphones on Compaq F750US not Working https://bugs.launchpad.net/bugs/225926 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
