I have a netbook with Debian 8 (before kali, and before that, ubuntu) And i got a weird problem (with all them): even without xserver running, its log off randomly without any warning.dmesg doesn't show anything weird. The weirdest thing it's if I connect an external screen through VGA, the problem stops; but if I disconnect the screen, the problem starts again.I've already reinstalled intel drivers, and there's no xorg.conf file in X11 directory.
Random log off without any warning
linux;debian;drivers