I've tried the solution at Ubuntu 19.04 cannot change brightness on laptop but it doesn't seem to be working for me. I am using Ubuntu 19.10 instead of 19.04 as in that answer.
The main script
xps-brightness.sh from that answer:
#!/bin/sh # Where the backlight brightness is stored BR_DIR="/sys/devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight" test -d "$BR_DIR" || exit 0 MIN=0 MAX=$(cat "$BR_DIR/max_brightness") VAL=$(cat "$BR_DIR/brightness") if [ "$1" = down ]; then VAL=$((VAL-6000)) else VAL=$((VAL+6000)) fi if [ "$VAL" -lt $MIN ]; then VAL=$MIN elif [ "$VAL" -gt $MAX ]; then VAL=$MAX fi PERCENT=`echo "$VAL / $MAX" | bc -l` export XAUTHORITY=/home/derek/.Xauthority # CHANGE "user" TO YOUR USER export DISPLAY=:0.0 echo "xrandr --output eDP-1 --brightness $PERCENT" > /tmp/xps-brightness.log xrandr --output eDP-1 --brightness $PERCENT echo $VAL > "$BR_DIR/brightness"
When I use the brightness keys on my keyboard, both the value in
$BR_DIR/brightness and the
/tmp/xps-brightness.log log file get updated, but the script doesn't seem to execute the
xrandr --output eDP-1 --brightness $PERCENT command. This command works when I enter it directly into a console or in a script such as
#!/bin/sh xrand --output eDP-1 --brightness .7
and then run