I've ran into this issue where the brightness control on my laptop will "repeat" for a second or so, even when tapped lightly.
The shortcuts are
Fn+End on this LG Z1 Pro Express Dual.
What I tried:
There is no
Fn lock. I tried toggling the BIOS setting for "sticky
Fn key" either way, with no result.
While the brightness adjustment is going on in these repeated little stages (like 5 FPS) the window manager is absolutely unresponsive, and takes a few seconds to come back. Can't even move the mouse while it's happening.
Update: I added
acpi_osi=Linux acpi_backlight=vendor to GRUB configuration, and now it doesn't repeat quite as much. Still goes 5 FPS while the display is "fading" and the indicator overlay is showing. Maybe it's not repeating, just tries to fade smoothly to new values and is really slow at doing that?
Doesn't seem to have a problem doing all the other compositing stuff though.