Set default LVDS brightness output for Ubuntu

Document NO.

2023102704
Category

Software Driver
Update Date

2023-11-14
Rev.

A1

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Model Name

All x86 Products

Due to the BIOS POST and Linux control the backlight brightness in different ways, if the brightness settings on both sides are different, there will be two stages of brightness display during the process from booting BIOS POST to Linux.

Based on the situation above, to avoid the two stage brightness display switching, we can make the command into a bootable script, and enter to Linux OS and automatically adjust the brightness to 70% or same as BIOS brightness settings.

Please download these two files (avalue-rc-local.service, rc.local) and refer to the following for the Linux command method. Or refer to the next page to copy and overwrite the contents to the original Linux file. (avalue-rc-local.service  rc-local.service, rc.local  rc.local)

Following is Ubuntu bootable service file and the LVDS brightness output setting file:

Bootable service file (rc-local.service)

# SPDX-License-Identifier: LGPL-2.1+
#
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.

# This unit gets pulled automatically into multi-user.target by
# systemd-rc-local-generator if /etc/rc.local is executable.
[Unit]
Description=/etc/rc.local Compatibility
Documentation=man:systemd-rc-local-generator(8)
ConditionFileIsExecutable=/etc/rc.local
After=network.target

[Service]
Type=forking
ExecStart=/etc/rc.local start
TimeoutSec=0
RemainAfterExit=yes
GuessMainPID=no

[Install]
WantedBy=multi-user.target
Alias=rc.local.service

LVDS brightness output setting file (rc.local)

#!/bin/bash

echo 70 > /sys/class/backlight/intel_backlight/brightness

exit 0

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