很多人在安装ubuntukylin之后，出现屏幕的亮度无法调节和无法保存的问题，可以尝试通过下面的方法解决：
1.解决reboot后无法保存屏幕亮度：
sudo gedit /etc/rc.local
打开后你会看到如下内容：
#!/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
插入这句话到代码中：
echo 0 > /sys/class/backlight/acpi_video0/brightness保证修改后代码如下，注意exit前的“#”
#!/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
其中echo 后面的值为0-10，对应为0到100%,如echo 5表示一半亮度保存后退出，重启就可以了。注意：大多数人都是acpi_video0，根据自己/sys/class/backlight/下面文件决定2、亮度调节亮度调节依赖与你的bios和内核版本，你可以尝试以下代码：kernel boot选项：当你启动系统时，出现在grup的屏幕时，按e键进行编辑，在kernel这一行添加：
nomodeset acpi_backlight=vendor
退出启动，如果能正常启动，就把这项选项添加到默认的选项中，编辑文件/etc/default/grub
# command line
sudo -e /etc/default/grub
# graphical
gksu gedit /etc/default/grub
把这一行改成如下：
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash nomodeset acpi_backlight=vendor"
保存，更新grup
sudo update-grub
如果还是没有解决问题的话请参照如下链接方法：
http://askubuntu.com/questions/3841/desktop-doesnt-remember-brightness-settings-after-a-reboot