Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    Option         "RegistryDwords" "EnableBrightnessControl=1"
EndSection

$ sudo apt-get install git dkms

$ git clone https://github.com/guillaumezin/nvidiabl.git
$ cd nvidiabl
$ sudo make dkms-install

$ sudo modprobe nvidiabl

$ sudo su
# echo 100 > /sys/class/backlight/nvidia_backligh/brightness

$ sudo modprobe -r nvidiabl
$ sudo modprobe nvidiabl max=100000 min=10

configuration: drigver=nouveau latency=0

sudo apt-get install linux-source
sudo apt-get install linux-headers-generic
sudo apt-get install nvidia-current-updates

sudo nvidia-settings

acpi_backlight=vendor