Save the screen light settings at shutdown and restore it at boot time, using OpenRC init scripts.

1. Install the package using the AUR tar ball

1. Install the package with pacman -S backlight-openrc

1. Clone this repo
2. Install the file backlight in /etc/init.d/ with

install -m=755 -oroot backlight /etc/init.d/backlight

After installing you should add the service to the system boot schedule with

rc-update add backlight

1. Just remove it with pacman

pacman -R backlight-openrc

1. First remove it from the system startup

rc-update del backlight -a

2. Then just delete the script from your system

 rm /etc/init.d/backlight