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Ubuntu 无法调节并保存屏幕亮度解决办法

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

GRUB_DEFAULT=0
#GRUB_HIDDEN_TIMEOUT
=0
GRUB_HIDDEN_TIMEOUT_QUIET
=true
GRUB_TIMEOUT
=3
GRUB_DISTRIBUTOR
=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT
=quiet splash
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 dont 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/she
#
# 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
exit
0


调节gamma值
➜  ~  xgamma -gamma .7
-> Red  1.000, Green  1.000, Blue  1.000
<- Red  0.700, Green  0.700, Blue  0.700

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