What should I do if Ubuntu fails to adjust and save the screen brightness?

In the Ubuntu system, sometimes the screen brightness is adjusted because the screen is too bright or too dark, but the screen brightness cannot be adjusted, or it cannot be saved after adjustment. How to solve this problem?

test environment:

Acer Aspire 5750G

NVIDIA GeForce GT630M

Ubuntu 12.04 x86_64

Other solutions similar circumstances .

Adjusting the screen brightness

Fn does not adjust the brightness of the screen. Because fn adjusts the /sys/class/backlight/acpi_video0/brightness file, and the I card file is /sys/class/backlight/intel_backlight/brightness.

First, the test code

Start the system, when the grub menu appears, press “e” edit, in the line with the Linux kernel path, add “acpi_backlight=vendor”, such as: Br>

linux /boot/vmlinuz-3.2.0-30-generic root=UUID=75c414be-2e17-407a-b699-94f6a398dff7 ro acpi_backlight=vendor quiet splash

If it starts normally, and use Fn can adjust the screen brightness, indicating success, and then the next step.

Second, modify grub

sudo vi /etc/default/grub

Find:

GRUB_CMDLINE_LINUX=“”

Change to:

GRUB_CMDLINE_LINUX=“acpi_backlight=vendor“

My grub file is as follows:

# 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=3

GRUB_DISTRIBUTOR= `lsb_release -i -s 2" /dev/null