After playing around with it for a while, the only way I seem to be able to reproduce this is by adjusting the brightness using the Fn+(Up/Down) keys. This happens both when I am plugged in and not. Also the note of switching using Ctrl+Alt+F1 and then back does seem to restore functionality on my machine.
After playing around with it for a while, the only way I seem to be able to reproduce this is by adjusting the brightness using the Fn+(Up/Down) keys. This happens both when I am plugged in and not. Also the note of switching using Ctrl+Alt+F1 and then back does seem to restore functionality on my machine.