Brightness Function Keys (F5 & F6) not working in RHEL 7, HP laptop

Question

Problem: Backlight function keys don't work in KDE, but brightness can be adjusted via "Display Brightness" GUI located in lower right power management icon.

Specs:

• OS: RHEL 7
• Window manager: KDE
• Graphics card: NVIDIA Quadro M1000M
• Laptop: HP ZBook Studio G3

Solutions attempted and failed:

• Appending each of the following to grub line: acpi_backlight=vendor acpi_backlight=video acpi_backlight=native acpi_backlight= acpi_backlight=none
• GRUB_CMDLINE_LINUX_DEFAULT="acpi_osi=" does not make the function buttons work and also has a side effect of not allowing me to change the brightness from the GUI or with changing the value in /sys/class/backlight/. Major fail

Answer 1

Unfortunately I was never able to get the function keys to lower the screen brightness.

Solution:

• Get nux-desktop for centos 7 repo
• Install xbacklight (testing xbacklight -10 and xbacklight +10 to validate it was going to work after install).
• Disabled nux-desktop in yum
• Setup keyboard shortcuts to lower/increase screen brightness. For some reason the 'Fn' button is not recognized in GNOME when setting up custom shortcut keys, so I had to use Ctrl + F5 and Ctrl + F6.

IMHO, this solution sucks, but it works.