How to adjust brightness on my Samsung Laptop after installing NVidia driver

After installing NVidia driver, you may not change LCD brightness.
You can fix this by simply adding the followings:

in /etc/X11/xorg.conf

Section “Device”
Identifier “Default Device”
Driver “nvidia”
Option “NoLogo” “True”
Option “RegistryDwords” “EnableBrightnessControl=1”
EndSection