When i just try adjusting brightness, the indicator changes but the screen does not change brightness. I have tried adding
acpi_backlight=vendor to my
grub file and also doing
echo x > sudo tee /sys/class/backlight/dell_backlight/brightness
echo x > sudo tee /sys/class/backlight/intel_backlight/brightness
Brightness used to change fine but now is not working on a new ubuntu install. I am using a dell xps 14 with a NVIDIA 630M using the
nvidia-340-updates driver &
nvidia prime. Also supports ivybridge graphics but I am using the 630m. Thanks in advance
/X11/xorg.conf.d/20-intel.conf did not fix my issue.
Model is Dell XPS 14-l421x
Updating to kernal
3.19.0-25-generic and ubuntu 15.04 did not fix my issues
The problem was the bios setting "Load legacy option rom" being set to Enabled, setting this to disabled fixed my backlight.