The Xbacklight no output have properties message can happen if your hardware has poor support or it can’t be detected properly by the xbacklight utility.

This might be fixed by using an xbacklight wrapper called acpilight. acpilight can also be used to control the display and keyboard backlight on modern laptops.

First, install the acpilight package:

sudo pacman -Syu acpilight

Add a udev rule to give access to users in the video group, this is needed because users don’t have permissions to alter sys files by default:

# /etc/udev/rules.d/90-backlight.rule

# Allow video group to control backlight and leds
SUBSYSTEM=="backlight", ACTION=="add", \
  RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness", \
  RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"

SUBSYSTEM=="leds", ACTION=="add", KERNEL=="*::kbd_backlight", \
  RUN+="/bin/chgrp video /sys/class/leds/%k/brightness", \
  RUN+="/bin/chmod g+w /sys/class/leds/%k/brightness"

Add your user to the video group:

sudo gpasswd -a your_user video