Brightness problem with Xubuntu

Question

I use Xubuntu Linux

Brightness is good without using suspend mode but after using suspend mode I got problem with brightness It's lower than before ! I need your help

Answer 1

http://www.iasptk.com/save-screen-brightness-settings-in-ubuntu-1204-laptop

Some Ubuntu laptops screen brightness reset to the lowest or highest on every boot and you have to configure the screen birghtness on every login.

To save the screen brightness settings in Ubuntu laptop.

Open a terminal window, and execute this command to edit /etc/rc.local:

sudo nano /etc/rc.local

Add this before the last line “exit 0″:

echo 5 > /sys/class/backlight/acpi_video0/brightness

number 5 is the value of your screen brightness. With this command check the maximum:

cat /sys/class/backlight/acpi_video0/max_brightness

Answer 2

Try modifying your /etc/default/grub file.

gksudo gedit /etc/default/grub

Edit the line: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

To: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Or: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"

Then run sudo update-grub and reboot.

Source: https://wiki.ubuntu.com/Kernel/Debugging/Backlight