Alright, but it would still be nice to have an error message when the user tries to set a different gamma/brightness and maybe a hint that colord calibration should be disabled for that to work. Actually it might be a good idea to have some error messages in colorramp_colord_fill() as well, in those cases where it fails.
Yes, (fake) brightness adjustment was a requested feature. I'm not really sure if the average user realizes that it is different from backlight adjustment.