Walter - the UI is horrible (really), but there are two things to consider - if the backlight can be adjusted the slider is enabled. If not, there is only the brightness control available.
PS: Horrible is the nicest word i can find for the state of the lxqt-config-brightness UI. Filed a bug a year ago iirc, but nobody stepped up and finally fixed it.
Walter - the UI is horrible (really), but there are two things to consider - if the backlight can be adjusted the slider is enabled. If not, there is only the brightness control available.
PS: Horrible is the nicest word i can find for the state of the lxqt-config- brightness UI. Filed a bug a year ago iirc, but nobody stepped up and finally fixed it.