This service attempts to bring automatic backlight for KDE. It was originaly developped on a Yoga Pro 7 running OpenSUSE Tumbleweed with Plasma. It might not work on other laptops depending on your configuration. Please provide feedback if it doesn't.
In order to build from source and install the service, simply run ./build_and_install.sh
cmake, libc-dev, libcxx-dev, libdbus-1-dev, PkgConfig, FindPkgConfig.cmake