h2059030

turned out my problem was something different: the X server enabled its SlowKeys feature (it showed up in Xorg.0.log after i had set the debug level higher), and was eventually caused by me holding shift pressed for 8 seconds. keeping it pressed other 8 seconds disabled that. see http://who-t.blogspot.co.at/2012/06/xkb-slowkeys.html for more details.

i'm experiencing the same behavior with the vanilla client. i have not evaluated if the solution works for me, but a tip to all those stuck with the same problem: simultaneously press alt+print+r. this releases the keyboard lock held by x, and you can alt+ctrl+f1 to a terminal. also, connecting an external keyboard worked for me.