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I'm trying to edit the brightness of my System76 laptop screen from my window manager i3wm. I've tried the following:
xbacklight -dec 10
sudo vim /sys/class/backlight/intel_backlight/brightness
Even with sudo, and chmod 777 I can't edit this file. Vim says "Fsync failed" when I try to write to it, and I have plenty of disk space available so that is not the problem
xrandr --output eDP-1 --brightness 0.5
this works, but it modulates brightness in software and doesn't have the increment/decrement abilities I want.