在安装Ubuntu Kylin后执行reboot总是无法保存好屏幕的亮度，下面是解决办法：
运行：sudo gedit /etc/rc.local
内容如下：
#!/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.
#exit 0
把echo 0 > /sys/class/backlight/acpi_video0/brightness放到代码中去，新代码如下：
#!/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 0 > /sys/class/backlight/acpi_video0/brightness
exit 0
注：后面两项exit是没有“#”的。
echo后面的值设0-10，对应为0到100%，如果设为echo 5就是50%的亮度，做更改后保存退出，重启后问题就得以解决了。