This sounds like the embedded controller is getting hung or loosing it's mind - stuff like fan control going haywire, hotkeys not working. Normally the way to temporarily cure this is to remove the AC and the battery and let the machine fully power down (as you did). I suggest when this happens again to run "dmesg > dmesg.log" and attach that to this bug report to what the kernel is reporting.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1048544 Title: LENOVO ThinkPad L512 (2597AB2) Fan speed freezes, and hotkeys stop working To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1048544/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
