ubuntu12.04修改屏幕亮度

      在使用ubuntu12.04LTS的时候，屏幕亮度是一个头疼的问题，动不动就是最亮的，很刺眼，在网上查询一些资料，发现也有人和我遇到过相同的问题。

      ubuntu有很多的版本，比如12.04、13.10等，在网上查询到的一些方法可能解决不了自己的问题，估计是系统版本不同所造成的原因。今天在网上看到一个，自己验证了一下，可以解决屏幕亮度最大化的问题。

      操作步骤：

• 将/etc/default/grub文件中的GRUB_CMDLINE_LINUX=""修改为GRUB_CMDLINE_LINUX="acpi_backlight=vendor"

• 向/etc/rc.local文件中添加echo 350 > /sys/class/backlight/intel_backlight/brightness

      修改后的文件内容：

• /etc/default/grub

# 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=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
#GRUB_CMDLINE_LINUX=""
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"

• /etc/rc.local

#!/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 350 > /sys/class/backlight/intel_backlight/brightness
exit 0

      操作流程：

ubuntu@ubuntu-K55VD:/home/wahaha$ su root
密码： 
root@ubuntu-K55VD:/home/wahaha# nano /etc/default/grub          
root@ubuntu-K55VD:/home/wahaha# update-grub
Generating grub.cfg ...
Warning: Setting GRUB_TIMEOUT to a non-zero value when GRUB_HIDDEN_TIMEOUT is set is no longer supported.
Found linux image: /boot/vmlinuz-3.8.0-37-generic
Found initrd image: /boot/initrd.img-3.8.0-37-generic
Found linux image: /boot/vmlinuz-3.8.0-36-generic
Found initrd image: /boot/initrd.img-3.8.0-36-generic
Found linux image: /boot/vmlinuz-3.8.0-35-generic
Found initrd image: /boot/initrd.img-3.8.0-35-generic
Found linux image: /boot/vmlinuz-3.8.0-29-generic
Found initrd image: /boot/initrd.img-3.8.0-29-generic
Found memtest86+ image: /boot/memtest86+.bin
done
root@ubuntu-K55VD:/home/wahaha# nano /etc/rc.local
root@ubuntu-K55VD:/home/wahaha# reboot