Need control brightness!! Like xrandr --output HDMI-0 --brightness 0.7 --gamma 0.6:0.6:0.6
Only one that worked for me - The DE's own (Gnome's and XFCE's) either didn't work or just messed stuff up. Only negative thing is, there's no pop-up asking whether you want to keep changes and that returns to previous setup after a timeout. grandr and lxrandr just messed things up and I don't remember which, biut one or the other was incomprehensible to use. It seems I can get it to work with my QBell FullHD TV only with nvidio proprietary drivers though - whether I try through VGA or HDMI, the nouveau acts like it's working: recognizes connected external VGA and/or HDMI, resolutions, even the desktop expands like there is a monitor on right of my laptop, but all I get on my TV is "no signal" - it must be a glitch in nouveau drivers somehow failing with RANDR extension.
very useful program for frequent work with the second monitor or TV
Does what it says on the tin.
Nice to have display tweaker