Kernel 5.8 breaks thinkpad x1 brightness control in KDE

After upgrade to kernel 5.8.3-2 plugging / unplugging power to my x1 carbon (6th gen) does not change monitor brightness. Resetting in KDE settings has no effect. Works fine in 5.7. I wonder if anyone else has seen this or knows a fix …

I had the same problem with my asus tuff fx505 since 5.7. After search the net for a fix and not find anyone, i made my personal workaround.
I created a script to change brightness on every boot.

  1. run xrandr to know the name of your output and noted
  2. create a file as an give ti exec permissions
  3. open the file and add this
xrandr --output "the name you noted before" --brightness 0.80 

you can change 0.80 to the valor you like
4. save it on your home
5. go to settings/autostart and add the script.

thanks for that but I want KDE to handle brightness as I plug and
unplug the AC power - I could make a custom ACPI script that
watches for plug events but really KDE should do this by
itself (and I am sure it will eventually).

I thing it isn’t a kde problem but a kernel/firmware instead. Anyway let’s hope it’ll fix!!