Open the terminal and follow the steps listed below:
1)sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf
2)sudo gedit /usr/share/X11/xorg.conf.d/20-intel.conf
3)Type the following lines
Section "Device" Identifier "card0" Driver "intel" Option "Backlight" "intel_backlight" BusID "PCI:0:2:0" EndSection
4)Save the file
5)Log out and then login
Open the terminal and follow the steps listed below:
1)sudo touch /usr/share/ X11/xorg. conf.d/ 20-intel. conf
2)sudo gedit /usr/share/ X11/xorg. conf.d/ 20-intel. conf
3)Type the following lines
Section "Device"
Identifier "card0"
Driver "intel"
Option "Backlight" "intel_backlight"
BusID "PCI:0:2:0"
EndSection
4)Save the file
5)Log out and then login