I have this problem... When Im on Ubuntu 16.04 (LTS) or basicly every Linux distro that i tried before, i have a bug. On open-source drivers, my brightness and gamma are normal, but when i use any nvidia driver (newer, older, doesnt matter), my gamma and brightness are way too dark. Im using a workaround with xgamma on startup, but its kinda not a permanent solution (because i use fullscreen apps and they reset the gamma upon exiting). So is there a way to set the same gamma that open-source driver has? Or do i have to use open-source driver until nvidia fixes it?