本文保留屏幕亮度方法适合使用笔记本的朋友，大家都知道，过亮的屏幕不但刺眼而且缩短LCD屏幕寿命，不幸的是，Ubuntu默认关机后并不保存当前屏幕亮度配置数据，每次开机都要重新设置亮度，很不方便。本文介绍的方法可以彻底解决这个问题！

1.修改/etc/default/acpi-support

ENABLE_LAPTOP_MODE=true

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

交流电模式下使用 laptop mode

#

# Enable laptop mode when on AC power.

#

ENABLE_LAPTOP_MODE_ON_AC=1

＃电池那也可设为1

使用 laptop mode 进行LCD亮度控制

#

# Should 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”

如果你不明白上面的设置的意思，可以参考下面的说明：

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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 the

# command:

#

# 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.

＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊

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Ubuntu 无法调节并保存屏幕亮度解决办法

[日期：2012-09-13]

测试环境：

Acer Aspire 5750G

NVIDIA GeForce GT630M

Ubuntu 12.04 x86_64

其他情况解决方法类似。

调节屏幕亮度

Fn不能调节屏幕的亮度。因为fn调节的是/sys/class/backlight/acpi_video0/brightness文件，而I卡的文件是/sys/class/backlight/intel_backlight/brightness。

一、测试代码

启动系统，出现grub菜单时，按“e”编辑，在有linux内核路径那一行，添加“acpi_backlight=vendor”，如：

linux    /boot/vmlinuz-3.2.0-30-generic root=UUID=75c414be-2e17-407a-b699-94f6a398dff7 ro acpi_backlight=vendor  quiet splash

如果能正常启动，且用fn能调节屏幕亮度，说明成功，接着下一步。

二、修改grub

sudo vi /etc/default/grub

找到：

GRUB_CMDLINE_LINUX=""

改为：

GRUB_CMDLINE_LINUX="acpi_backlight=vendor“

我的grub文件如下：

# If you change this file, run 'update-grub' afterwards to update

#

# /boot/grub/grub.cfg.

#

# For full documentation of the options in this file, see:

#

#   info -f grub -n 'Simple configuration'

G

GRUB_DEFAULT=0

#

#GRUB_HIDDEN_TIMEOUT=0

G

GRUB_HIDDEN_TIMEOUT_QUIET=true

G

GRUB_TIMEOUT=3

G

GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`

G

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

G

GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

#

# Uncomment to enable BadRAM filtering, modify to suit your needs

#

# This works with Linux (no patch required) and with any kernel that obtains

#

# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)

#

#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

#

# Uncomment to disable graphical terminal (grub-pc only)

#

#GRUB_TERMINAL=console

#

# The resolution used on graphical terminal

#

# note that you can use only modes which your graphic card supports via VBE

#

# you can see them in real GRUB with the command `vbeinfo'

#GRUB_GFXMODE=640x480

#

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux

#

#GRUB_DISABLE_LINUX_UUID=true

#

# Uncomment to disable generation of recovery mode menu entries

#

#GRUB_DISABLE_RECOVERY="true"

#

# Uncomment to get a beep at grub start

#

#GRUB_INIT_TUNE="480 440 1"

更新grub.cfg

?  ~  sudo update-grub

查看grub.cfg 发现其中每个启动项都加入了“acpi_backlight=vendor”

?  ~  vi /boot/grub/grub.cfg

设定屏幕初始亮度

重启后发现，屏幕亮度又恢复为最大亮度。

查看影响屏幕亮度的文件

?  ~  vi /sys/class/backlight/intel_backlight/brightness

调节几次屏幕亮度发现其中数值会改变，我的笔记本数值范围为0～976。

手动修改该数值，会发现屏幕亮度随之改变(需要root用户执行)：

?  ~  su

Password:

root@ www.linuxidc.com :/home/congbo# echo 500 > /sys/class/backlight/intel_backlight/brightness

因此，将该语句添加到 /etc/rc.local 就能开机自动设定屏幕初始亮度了。

修改/etc/rc.local如下(需要root用户执行)：

#!/bin/sh -e

#

#

#

# rc.local

#

#

#

# This script is executed at the end of each multiuser runlevel.

#

# Make sure that the script will “exit 0″ on success or any other

#

# value on error.

#

#

#

# In order to enable or disable this script just change the execution

#

# bits.

#

#

#

# By default this script does nothing.

echo 500 > /sys/class/backlight/intel_backlight/brightness

e

exit 0

调节gamma值

?  ~  xgamma -gamma .7

-> Red  1.000, Green  1.000, Blue  1.000