Linux下调节亮度的问题

sudo vi /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="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" 

# Uncomment to get a beep at grub start 
#GRUB_INIT_TUNE="480 440 1"

sudo update-grub