I had to change localhost in sudoers to the name of my computer!
Switched over to the advanced brightness and it worked, so did drakroam.
On the brightness procedure from the regular section - It works partially.
I had to add a line for backlight-toggle to the sudoers file to get it to work at all.
The Fn - down arrow lowers the brightness to minimum right away. The Fn - up arrow has no effect. The Fn - F5 keys bring the brightness up a notch but no down at all.
And yes the system is all up to date including kernel 184.108.40.206.
Hope this helps.
Strange. Have you left the previous kernel installed, and if so, which one are you actually booting to?
Maybe different versions of the hardware give different key readings, in which case can you open a terminal as USER, and type the following lines:
The first line stops xbindkeys to stop it having any effect, the second puts up a small window, which you should click on with your mouse. Then if you press in all the Fn-F key combinations, you should see what codes they are returning on your system. You may have to change the codes in your .xbindkeysrc file.