1 files changed, 56 insertions, 0 deletions
diff --git a/bin/set_backlight b/bin/set_backlight
new file mode 100755
index 0000000..c110321
--- /dev/null
+++ b/bin/set_backlight
@@ -0,0 +1,56 @@
+#!/bin/bash
+# Script to set backlight on startup on Lenovo W540 using
+# /sys/class/backlight/intel_backlight/brightness
+# This must be run as root.
+
+# check if root
+if [[ $EUID -ne 0 ]];then
+  echo "This must be run as root."
+else
+  # get current and maximum brightness, set maximum steps allowed
+  brightness_current=$(cat /sys/class/backlight/intel_backlight/brightness)
+  brightness_max=$(cat /sys/class/backlight/intel_backlight/max_brightness)
+  brightness_max=$(($brightness_max-1000))
+  brightness_steps=20
+  brightness_steps_width=$(($brightness_max/$brightness_steps))
+  brightness_new=0
+  # if first parameter to this script is a number
+  re='^[0-9]+$'
+  if [[ $1 =~ $re ]]; then
+    echo "Direct step called"
+    if [[ $1 -gt brightness_steps && $1 -ne 0 ]];then
+      brightness_new=$(($1*brightness_steps_width))
+    fi
+  elif [[ $1 == "up" || $1 == "down" ]];then
+    brightness_calc=$(($brightness_current / $brightness_steps_width))
+    case $1 in
+      "up" )
+        brightness_calc=$((($brightness_calc+1) * $brightness_steps_width))
+        echo "brightness_calc: $brightness_calc"
+        echo "brightness_max: $brightness_max"
+        if [[ $brightness_max -gt $brightness_calc ]];then
+          echo "true"
+          brightness_new=$brightness_calc
+        else
+          echo "false"
+          brightness_new=$brightness_current
+        fi
+        ;;
+      "down" )
+        brightness_calc=$((($brightness_calc-1) * $brightness_steps_width))
+        echo "brightness_calc: $brightness_calc"
+        if [[ $brightness_calc -gt 0 ]];then
+          brightness_new=$brightness_calc
+        else
+          brightness_new=$brightness_current
+        fi
+        ;;
+    esac
+    echo "Step called with: $1"
+  fi
+  echo $brightness_current
+  echo $brightness_new
+  # set to 234 (around 4th step)
+  #echo 234 > /sys/class/backlight/intel_backlight/brightness
+  echo $brightness_new > /sys/class/backlight/intel_backlight/brightness
+fi