[SOLVED] How to change the Notebook LCD backlight brightness

[glup]

I hope I post my question at the right place.

My Panasonic Toughbook CF-31 Mk 3 shall be migrated to LM from Windows.
The current problem is that I can't change under Linux Mint the Backlight brightness. The key combination <Fn>+<F1> to reduce and <Fn>+<F2> to increase the brightness display a nice icon on the display while I press them but do not what the icon tells... It seams to be fixed at the medium brightness. During night much to bright and in the sun much to low.

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~$ inxi -Fxxxrz
System:
  Host: UGA Kernel: 5.3.0-51-generic x86_64 bits: 64 compiler: gcc v: 7.5.0 
  Desktop: Cinnamon 4.4.8 wm: muffin 4.4.2 dm: LightDM 1.26.0 
  Distro: Linux Mint 19.3 Tricia base: Ubuntu 18.04 bionic 
Machine:
  Type: Laptop System: Panasonic product: CF-31SBL741M v: 003 
  serial: <filter> Chassis: type: 10 v: 001 serial: <filter> 
  Mobo: Panasonic model: CF31-3 v: 1 serial: <filter> 
  BIOS: American Megatrends v: 3.00L14 date: 07/03/2014 
Battery:
  ID-1: BAT1 charge: 51.6 Wh condition: 80.7/91.0 Wh (89%) volts: 11.1/10.7 
  model: Panasonic CF-VZSU46 type: Li-ion serial: <filter> 
  status: Discharging 
CPU:
  Topology: Dual Core model: Intel Core i5-3320M bits: 64 type: MT MCP 
  arch: Ivy Bridge rev: 9 L2 cache: 3072 KiB 
  flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 20753 
  Speed: 1197 MHz min/max: 1200/3300 MHz Core speeds (MHz): 1: 1197 2: 1197 
  3: 1197 4: 1197 
Graphics:
  Device-1: Intel 3rd Gen Core processor Graphics vendor: Matsushita 
  driver: i915 v: kernel bus ID: 00:02.0 chip ID: 8086:0166 
  Display: x11 server: X.Org 1.20.5 driver: modesetting unloaded: fbdev,vesa 
  resolution: 1024x768~60Hz 
  OpenGL: renderer: Mesa DRI Intel Ivybridge Mobile v: 4.2 Mesa 19.2.8 
  compat-v: 3.0 direct render: Yes 
Audio:
  Device-1: Intel 7 Series/C216 Family High Definition Audio 
  vendor: Matsushita driver: snd_hda_intel v: kernel bus ID: 00:1b.0 
  chip ID: 8086:1e20 
  Sound Server: ALSA v: k5.3.0-51-generic 
Network:
  Device-1: Intel 82579LM Gigabit Network vendor: Matsushita driver: e1000e 
  v: 3.2.6-k port: f080 bus ID: 00:19.0 chip ID: 8086:1502 
  IF: enp0s25 state: down mac: <filter> 
  Device-2: Intel Centrino Advanced-N 6235 driver: iwlwifi v: kernel 
  port: f040 bus ID: 09:00.0 chip ID: 8086:088e 
  IF: wlp9s0 state: up mac: <filter> 
  IF-ID-1: wwan0 state: down mac: <filter> 
Drives:
  Local Storage: total: 465.76 GiB used: 13.00 GiB (2.8%) 
  ID-1: /dev/sda vendor: Samsung model: SSD 860 EVO 500GB size: 465.76 GiB 
  speed: 3.0 Gb/s serial: <filter> rev: 4B6Q scheme: MBR 
Partition:
  ID-1: / size: 447.03 GiB used: 12.76 GiB (2.9%) fs: btrfs dev: /dev/sda6 
  ID-2: /boot size: 453.0 MiB used: 242.7 MiB (53.6%) fs: ext4 
  dev: /dev/sda1 
  ID-3: /home size: 447.03 GiB used: 12.76 GiB (2.9%) fs: btrfs 
  dev: /dev/sda6 
  ID-4: swap-1 size: 3.81 GiB used: 0 KiB (0.0%) fs: swap dev: /dev/sda5 
Sensors:
  System Temperatures: cpu: 58.0 C mobo: N/A 
  Fan Speeds (RPM): N/A 
Repos:
  No active apt repos in: /etc/apt/sources.list 
  Active apt repos in: /etc/apt/sources.list.d/eh5-pulseaudio-a2dp-bionic.list 
  1: deb http://ppa.launchpad.net/eh5/pulseaudio-a2dp/ubuntu bionic main
  Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list 
  1: deb http://mirror.netcologne.de/linuxmint/packages tricia main upstream import backport
  2: deb http://ftp-stud.hs-esslingen.de/ubuntu bionic main restricted universe multiverse
  3: deb http://ftp-stud.hs-esslingen.de/ubuntu bionic-updates main restricted universe multiverse
  4: deb http://ftp-stud.hs-esslingen.de/ubuntu bionic-backports main restricted universe multiverse
  5: deb http://security.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse
  6: deb http://archive.canonical.com/ubuntu/ bionic partner
  Active apt repos in: /etc/apt/sources.list.d/tvheadend.list 
  1: deb https://apt.tvheadend.org/stable bionic main
Info:
  Processes: 257 Uptime: 2h 18m Memory: 7.64 GiB used: 2.51 GiB (32.8%) 
  Init: systemd v: 237 runlevel: 5 Compilers: gcc: 7.5.0 alt: 7 Shell: bash 
  v: 4.4.20 running in: gnome-terminal inxi: 3.0.32  

[glup]

I found myself a solution:

1. The redirect-brightness script from https://askubuntu.com/questions/1045624 ... tness-prob
2. Change in the script

   Code: Select all

   WatchDriver="/sys/class/backlight/panasonic"
   PatchDriver="/sys/class/backlight/intel_backlight"

3. Test it:

   Code: Select all

   sudo redirect-brightness -l

   and press Fn + F1 resp Fn + F2 multiple times, end Test with Ctrl + c
4. Create a systemd service unit /etc/systemd/system/redirect-brightness.service to start it after boot

   Code: Select all

   [Unit]
   Description=Redirect Backlight Brightness from one driver to another
   
   [Service]
   ExecStart=/usr/local/bin/redirect-brightness
   
   [Install]
   WantedBy=basic.target
   

   Install, enable and start the service:

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   sudo chmod 664 /etc/systemd/system/redirect-brightness.service
   sudo systemctl daemon-reload
   sudo systemctl enable redirect-brightness.service
   sudo systemctl start redirect-brightness.service
   

[atzekatze]

OMG, thank you so much, been struggling with this for so long now!