I have the battery modes set to change the brightness when changing from power cord to battery.
Sometimes when I resume the computer from sleep mode it immediately asks for root password to change the brightness while having the brightness set unusually low (at minimum I believe, which isn’t even in my power profiles)
It may seem like a small problem if you know the password… which everyone doesn’t, I hope.
Otherwise brightness control works just fine.
Thinkpad T61 quadro nvs 140