Ubuntu11.10 brightness cannot be adjusted and screen brightness cannot be saved Solution

After several failed changes and reinstalls, I finally found a solution in answers on the official website: 1. The screen brightness cannot be saved after reboot: [cpp] sudogedit/etc/rc. after opening local, you will see the following content :#! /Bin/sh-e # & nbsp

After several failed changes and reinstalls, I finally found a solution on the official website's answers:

1. The screen brightness cannot be saved after reboot is solved:

[Cpp] 
 
 

  
  
Sudo gedit/etc/rc. local
  
  

  
  
After opening the file, you will see the following content:
  
  

  
  
#! /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

 
 

Insert this sentence to the Code:

echo 0 > /sys/class/backlight/acpi_video0/brightness

Make sure that the modified Code is as follows. Note the "#" Before exit.

[Cpp] 
 
 

  
  
#! /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
 
 
 
The value after echo is 0-10, corresponding to 0 to 100%. For example, echo 5 indicates half brightness.

Save and exit. Restart.

Note: Most people use acpi_video0, which is determined by their/sys/class/backlight/file.

2. brightness adjustment

Brightness adjustment depends on your bios and kernel version. You can try the following code:

Kernel boot options:

When you start the system and appear on the grup screen, press the e key to edit and add the following lines in the kernel line:

[Cpp]

1. Nomodeset acpi_backlight = vendor

Note: Some hardware may be different. [Cpp]

1. Intel-nomodeset acpi_backlight = intel Acer-acpi_backlight = acer_acpi or even acpi_osi = Linux acpi_backlight = legacy.

My computer is acer 4830tg. I directly wrote = vendor, which can also work normally. You can also search for the options you want to set through google.

[Cpp]

1. Quiet splash nomodeset acpi_backlight = vendor

Exit startup. If it can be started normally, add this option to the default option and edit the file. /etc/default/grub

[Cpp]

1. # Command line
2. Sudo-e/etc/Default/Grub
4. # Graphical
5. Gksu gedit/etc/Default/Grub

Change this line to the following:
[Cpp]

1. GRUB_CMDLINE_LINUX_DEFAULT ="Quiet splash nomodeset acpi_backlight = vendor"

Save and update grup

[Cpp]

1. Sudo update-grub