Hi, same problem here with a intel GPU (i5 CPU) and "Linux samuel 3.2.0-4-amd64 #1 SMP Debian 3.2.39-2 x86_64 GNU/Linux". It is reproducible with scroll in LibreOffice and disappeared after replace of the graphic card by nvidia. I have an other hardware with a i5 CPU and intel GPU which freeze sometime without any user interaction. On both systems I can move the mouse cursor and change with Ctrl+Alt+F1 to the terminal.