From c20416644b6b4a18bd84e91b98bd6230b4598c9d Mon Sep 17 00:00:00 2001
From: Jan Philipp Timme <jan.philipp@timme.it>
Date: Mon, 25 Mar 2019 16:02:50 +0100
Subject: [PATCH] Save hints about backlight hack on laptop

---
 sbin/99-intelbacklighthack.rules |  1 +
 sbin/backlighthack.sh            | 14 ++++++++++++++
 2 files changed, 15 insertions(+)
 create mode 100644 sbin/99-intelbacklighthack.rules
 create mode 100755 sbin/backlighthack.sh

diff --git a/sbin/99-intelbacklighthack.rules b/sbin/99-intelbacklighthack.rules
new file mode 100644
index 0000000..bb11ff0
--- /dev/null
+++ b/sbin/99-intelbacklighthack.rules
@@ -0,0 +1 @@
+ACTION=="change", SUBSYSTEM=="backlight", RUN+="/usr/local/sbin/backlighthack.sh"
diff --git a/sbin/backlighthack.sh b/sbin/backlighthack.sh
new file mode 100755
index 0000000..f23adf0
--- /dev/null
+++ b/sbin/backlighthack.sh
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+intelmaxbrightness=`cat /sys/class/backlight/intel_backlight/max_brightness`
+acpimaxbrightness=`cat /sys/class/backlight/acpi_video0/max_brightness`
+scale=`expr $intelmaxbrightness / $acpimaxbrightness`
+acpibrightness=`cat /sys/class/backlight/acpi_video0/brightness`
+newintelbrightness=`expr $acpibrightness \* $scale`
+curintelbrightness=`cat /sys/class/backlight/intel_backlight/actual_brightness`
+
+if [ "$newintelbrightness" -ne "$curintelbrightness" ]; then
+    echo $newintelbrightness > /sys/class/backlight/intel_backlight/brightness
+fi
+
+exit 0