Package: xbacklight Version: 1.2.1-1 Followup-For: Bug #837477 Disregard my bug report. I think it is actually the same bug as this: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=833508#20
The workaround found by o...@bluemonk.de in that thread (which works for me) is to put: Section "Device" Identifier "Intel" Driver "intel" # Option "AccelMethod" "uxa" EndSection in /etc/X11/xorg.conf -- System Information: Debian Release: stretch/sid APT prefers testing APT policy: (500, 'testing') Architecture: amd64 (x86_64) Kernel: Linux 4.6.0-1-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) Versions of packages xbacklight depends on: ii libc6 2.23-5 ii libxcb-randr0 1.11.1-1.1 ii libxcb-util0 0.3.8-3 ii libxcb1 1.11.1-1.1 xbacklight recommends no packages. xbacklight suggests no packages. -- no debconf information