I have Ubuntu 16.04LTS running on my Dell XPS 15 9550. Until yesterday the fn-key for setting the brightness was able to set the brightness level to 0 (shutting backlight off completely) which I absoluetly appreciated while starting a movie on an external display. After the firmware update yesterday this feature is gone :(.
I searched the internet for a while and found the possibility to switching the backlight off by entering the command:
echo 0 > /sys/class/backlight/intel_backlight/brightnes
This actually does exactly what I want. But if I set the brightness to the lowest level by pressing fn-key it stops at 1.
I can see that by the command
Is there a way to change the minimum brightness level to zero by pressing the fn-key?
-- Edit --
According to the post Can I adjust the minimum brightness for my laptop's LCD? there is a way of setting this over the fn-keys. But the script
is never called (Following the tutorial https://help.ubuntu.com/community/LaptopSpecialKeys).
acpi_listen gives me
video/brightnessdown BRTDN 00000087 00000000
But I was not able to figure out which script is actually triggered by the event (so far).