Originally Posted by JimBowen
Just as an update/bump, I'd like to say that this is also affecting me, ever since I bought my new laptop last September.
Clevo M860TU / 9800M GTS, with various drivers from whatever was around last September, up to the very latest beta driver: 190.18
No control from laptop hotkeys, or in any software tools. Nothing in /proc/acpi/video or in /sys/class/backlight.
Backlight seems to be stuck on minimum, as I can't use it if I'm near a window.
If you are stuck on dim, try using the brightness hotkeys before the kernel loads (at the grub prompt). It actually works there for me, and stays at whatever I set it to between reboots. I just wish I could adjust it once I am booted up.