my small workaround to change the brightness:
1. ctrl+alt+F1 2. type user und password 3. sudo -s 4. echo -n xx > /proc/acpi/video/NVID/LCD/brightness 5. ctrl+alt+F7
*4. f.e. xx = 30
my small workaround to change the brightness:
1. ctrl+alt+F1 video/NVID/ LCD/brightness
2. type user und password
3. sudo -s
4. echo -n xx > /proc/acpi/
5. ctrl+alt+F7
*4. f.e. xx = 30