I'm new to linux systems in general (I'm using Ubuntu 16.04 LTS) and I'm having difficulty in changing the brightness of my notebook.
When I use the Fn+F8 or Fn+F9 the brightness bar shows up but there is no change in the actual brightness of the screen.
I tried every method discribed in this post (How to adjust screen brightness in Ubuntu 14.04 (Trusty Tahr)?) to no success.
Installing and using the xbacklight has no effect, same for editing the brightness file in the "intel_backlight" file.
Anyone knows how to solve this?