Python script to fix brightness control.
On some Optimus sytem, graphical tools to control brightness will write to /sys/class/backlight/acpi_video0/brightness. However, this isn't always the file that really controls the brightness.
This script is here to act as a bridge and to forward brightness update to the correct file.
Just make brigthnessd.py autostart.
Systemd instruction:
Copy the brightnessd.py somewhere on your system. Edit the brightnessd.service file so that
ExecStart points to the correct file. Then enable the service: systemctl enable brightnessd.