Add notes on how light was made to work with a non-root user.

tasks/workstation/linux/software/i3.yml

@@ -45,3 +45,25 @@
     owner: "{{ user }}"
     group: "{{ user }}"
     mode: '0664'
+
+# TBD: Automate getting the brightness keys to work.
+#
+# User is already part of the video group. Just need to configure udev rules.
+#
+# Get the folder name from here: `ls /sys/class/backlight/`
+#
+# That is your <DEVICE> for the following lines, which go here: /etc/udev/rules.d/backlight.rules
+# ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="<DEVICE>", RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness"
+# ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="<DEVICE>", RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"
+#
+# So, for example:
+# [18:12:20 root@device ~]# cat /etc/udev/rules.d/backlight.rules
+# ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="intel_backlight", RUN+="/bin/chgrp video /sys/class/backlight/%k/brightness"
+# ACTION=="add", SUBSYSTEM=="backlight", KERNEL=="intel_backlight", RUN+="/bin/chmod g+w /sys/class/backlight/%k/brightness"
+# [18:12:21 root@device ~]#
+#
+# It then required a reboot. Doing the commands below was not enough.
+#
+# # sudo udevadm control --reload-rules  ^C
+# # sudo udevadm trigger
+#