I have a System 76 laptop with nvidia dedicated graphics and am having trouble with the brightness adjustment controls in Pantheon. I have installed the system76-driver-nvidia from their ppa.
I have tried to use the inotify/xbacklight based solution detailed here
http://sub-pop.net/post/fedora-23-on-system76-oryx-pro/
(which basically uses information from /proc and xbacklight to adjust the brightness) and it doesn't have any effect nor any helpful errors in the logs. This is how I get the display to work properly in GNOME3 on arch.
I am hoping that since one of the Elementary OS devs works at system 76 there is a solution that I just haven't found. Thank you in advance for any help that you can give!