Actually, most monitors support the DDC/CI protocol [1]. But I think implementations tend to be spotty hence Windows (for example) doesn't show a brightness sli

Actually, most monitors support the DDC/CI protocol [1]. But I think implementations tend to be spotty hence Windows (for example) doesn't show a brightness slider in some configurations. Third party apps exist though (e.g., TwinkleTray [2]). [1] https://en.m.wikipedia.org/wiki/Display_Data_Channel https://en.m.wikipedia.org/wiki/Display_Data_Channel [2] https://twinkletray.com/ https://twinkletray.com/