I'm running 12.04 on a Lenovo ThinkPad Edge. I'm having these possibly related issues with things that worked perfectly when I installed Ubuntu:
Most of the Fn-keys worked seamlessly after I freshly installed Ubuntu, most importantly Fn+F1/F2/F3 for mute/volume control and Fn+F7/F8 for brightness. Recently they stopped working all together and the Fn-button does nothing at all.
When I close the lid on the laptop the computer doesn't go to suspend mode like it used to (and still is set to do), it just goes on running and doesn't register when I close the lid.
I noticed these two things within the same day. I haven't changed any settings that relates to these things but I've recently installed recommend updates.
Update: It's a BIOS issue with Thinkpad Edge. Removing and reinserting the battery solved both problems (as explained here: Ubuntu on Thinkpad Edge 11/13/14/15).