How to save the screen brightness of a notebook in Ubuntu

The screen brightness retention method in this article is suitable for the use of notebook friends, we all know that the bright screen not only glare but also shorten the LCD screen life, unfortunately, ubuntu does not save the current screen brightness configuration data after it is turned off by default. it is inconvenient to reset the brightness every time it is started. The methods described in this article can completely solve this problem! 1. Modify/etc/default/acpi-supportENABLE_LAPTOP_MODE = true2. Modify/etc/laptop-mode/laptop

The screen brightness retention method in this article is suitable for the use of notebook friends, we all know that the bright screen not only glare but also shorten the LCD screen life, unfortunately, ubuntu does not save the current screen brightness configuration data after it is turned off by default. it is inconvenient to reset the brightness every time it is started. The methods described in this article can completely solve this problem!

1. Modify/etc/default/acpi-support
ENABLE_LAPTOP_MODE = true

2. Modify/etc/laptop-mode/laptop-mode.conf

Laptop mode in alternating current mode

#
# Enable laptop mode when on AC power.
#
ENABLE_LAPTOP_MODE_ON_AC = 1
# The battery can also be set to 1.
LCD brightness control using laptop mode
#
# Shocould laptop mode tools control LCD brightness?
#
CONTROL_BRIGHTNESS = 1
#
# Commands to execute to set the brightness on your LCD
#
BATT_BRIGHTNESS_COMMAND = "echo 0 ″
LM_AC_BRIGHTNESS_COMMAND = "echo 9 ″
NOLM_AC_BRIGHTNESS_COMMAND = "echo 9 ″
BRIGHTNESS_OUTPUT = "/sys/class/backlight/acpi_video1/brightness"

If you do not understand the preceding settings, refer to the instructions below:

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# * If your system has the file "/proc/acpi/video/VID/LCD/brightness" (VID may
# Be VID1 or similar), use this file as BRIGHTNESS_OUTPUT, and use
# The command "echo". The possible values can be listed using
# Command: www.linuxidc.com
#
# Cat/proc/acpi/video/VID/LCD/brightness
# * If you have a file/sys/class/backlight /... /Brightness, then you can use
# That file as BRIGHTNESS_OUTPUT, and the command "echo".
#
# As far as I understand it the values are between 0 and
# The value contained in the file/sys/class/backlight /... /Max_brightness.
**********************************