Brightness
sudo gedit /etc/default/grub
find this line : GRUB_CMSLINE_LINUX_DEFAULT="quiet splash"
change to: GRUB_CMDLINE_LINUX_DEFAULT=
"quiet splash acpi_backlight=vendor"
and save it
then cmd > sudo update-grub
Brightness
sudo gedit /etc/default/grub
find this line : GRUB_CMSLINE_LINUX_DEFAULT="quiet splash"
change to: GRUB_CMDLINE_LINUX_DEFAULT=
"quiet splash acpi_backlight=vendor"
and save it
then cmd > sudo update-grub