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I have a ASUS UL30VT and just installed Ubuntu 14.04 LTS. The screen brightness was at level 0.

Attempt 1: so I navigated to find the screen brightness slider under System Settings>Brightness&Lock. Moving the slider did not affect the screen brightness.

Attempt 2: I used the hotkey on my keyboard fn+F6 for brightness up and fn+F5 for brightness down. The symbol at the top right of the screen showing that the brightness changes shows, but the screen brightness never changed.

Attempt3: I tried the answer in this askubuntu question here and it learned me the following. Running ls in /sys/class/backlight/ yields 

asus_laptop
intel_backlight

so apparently i have duplicate settings. Moving the slider in System Settings>Brightness&Lock adjusts the values in asus_baklight\brightness. Manually editing the file intel_backlight\brightness makes the screen changed, just as i hope.

So how do I make the system event of changing screen brightness link to the correct brightness file?

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LudvigH
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1 Answers1

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Found another solution that may work for you

Edit your grub file:

sudo gedit /etc/default/grub

change the line line

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to 

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"

then save and exit. Run

sudo update-grub

then reboot your PC

This should add its own backlight control as intel_backlight, adding this line forces acpi to use the Intel backlight.

If this doesn't work you can try the information in Brightness Adjustment Fatal Freeze + Odd boot screen start up error

this talks about creating an entry in /usr/share/X11/xorg.conf.d/20-intel.conf that looks something like this:

Section "Device"
        Identifier  "card0"
        Driver      "intel"
        Option      "Backlight"    "intel_backlight"
        BusID       "PCI:0:2:0"
EndSection
John Orion
  • 2,801