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
and
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
EDIT:
creating /X11/xorg.conf.d/20-intel.conf
did not fix my issue.
Model is Dell XPS 14-l421x
kernal version 3.16.0-45-generic
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.