Comment 3 for bug 1001554

Similar experience on two different systems with Ubuntu 12.04 installed:

1) i386 (32-bit) on eeepc 904HA hardware
2) amd64 on Dell Optiplex 990 hardware

Both systems show same symptoms: clicking on "sound settings" from the indicator-sound, and then the "input" tab shows no devices. HOWEVER, the microphone works! If I run skype, then the indicator-sound dropdown menu will show a slider for microphone (which works properly).

lspci on the Optiplex shows:
00:1b.0 Audio device: Intel Corporation 6 Series/C200 Series Chipset Family High Definition Audio Controller (rev 04)

This is potentially a duplicate of bug #1003671 under gnome-control-center.