I have 2 files in
intel_backlight is the one which controls my screen brightness (echo/cat), however
acpi_video0 is the default.
By default, the service
systemd-backlight@acpi_video0.service is enabled which should save/restore brightness at shutdown/startup, but it doesn't work since it points to the wrong file.
When trying to enable
systemd-backlight@intel_backlight.service instead, I get this message:
The unit files have no [Install] section. They are not meant to be enabled using systemctl. Possible reasons for having this kind of units are: 1) A unit may be statically enabled by being symlinked from another unit's .wants/ or .requires/ directory. 2) A unit's purpose may be to act as a helper for some other unit which has a requirement dependency on it. 3) A unit may be started when needed via activation (socket, path, timer, D-Bus, udev, scripted systemctl call, ...).
How do I fix this?