KDE Display Brightness Control Not Working on OpenMandriva

I am currently using OpenMandriva Lx ROME and I love it. It boots and loads really fast on my AMD Ryzen laptop. Unfortunately, KDE's brightness control is not working and I have to use xrandr to control the brightness manually.

The Simple Solution

After reading random forums about this not-really-uncommon issue, I've successfully solved the issue by these following simple steps:

1. Using your favourite text editor, edit /etc/default/grub
   In GRUB_CMDLINE_LINUX_DEFAULT
   remove acpi_backlight=vendor
   then, add amdgpu.backlight=0
2. Update grub:
   sudo grub2-mkconfig -o /boot/grub2/grub.cfg
3. Reboot the system. Now, the KDE's brightness control should work properly.