我的是Nvida显卡

sudo vi /etc/X11/xorg.conf
把
Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
   EndSection
改成
Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    Option "RegistryDwords" "EnableBrightnessControl=1"
EndSection
然后我的fn+上下 就可以调节屏幕亮度了