Hey. So I made the dumb decision of not backing up my /etc/default/grub while trying to get my brightness keys to work the way they should. Now, when I go to adjust the brightness from the system menu, there is no bar. The keys also do not display an overlay like the volume control keys and keyboard brightness keys. In short, I completely removed the keys' functionality rather than adding to it.
This is the line that I edited in /etc/default/grub:
GRUB_CMDLINE_LINUX_DEFAULT=
I remember that before I edited it, it mentioned modprobe. I feel that if I just add that line back and update-grub, I should be able to adjust my brightness through the menu and with the fn keys. So, if any of you are running Kali on a MacBook Pro, could you open /etc/default/grub and search for the line that I posted? Then just let me know what yours says. Or, if anyone knows of a different way to fix the problem let me know. I attached a screen shot to show you exactly what I'm talking about. There should be a little slider to adjust brightness.
