Im on KDE Manjaro.
I have an OLED panel on my Dell XPS 15 7590 Laptop.
Here https:// wiki.archlinux. org/index.php/Dell_XPS_15_7590#Backlight I read to install linux-oled from the AUR.
Installing linux-oled I had this problem:
==> Verifying source file signatures with gpg...
archlinux-linux git repo ... FAILED (unknown public key 3B94A80E50A477C7)
==> ERROR: One or more PGP signatures could not be verified!
Failed to build linux-oled
This worked! Now I can finally control my brightness!
Thank you very much
Sorry if I didnt quite understand what you meant at first. Still new to linux. And manjaro as a first distro is tuffer than others I believe.