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The brightness keys on my Dell N4010 with Ubuntu 12.04 is causing ubuntu to freeze on a black screen if i press the BrightUp and BrightDown key(s) 3-4 times. I think this is a bug which was noticed in 10.04 and was patched, but its giving problem in 12.04 again to me. I tried remapping and disabling the brightness keys but it did not work out. Please help.

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Edit "/etc/default/grub" as root.

gksu gedit /etc/default/grub

Now, look for the line that looks like:


Append "acpi_backlight=vendor acpi_osi=Linux" to the end of that line, before the end quotes, so that the line now looks something like this:

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

Save and close the file, and run the following command:

sudo update-grub

Now, reboot, and test out the brightness keys. They should be working correctly now.

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This worked before, on my ubuntu 12.10. Not working anymore on ubuntu 13.04. – FRD Jul 23 '13 at 9:40

I've managed to get this bug solved!

The answer is here:

Create the file /usr/share/X11/xorg.conf.d/20-intel.conf with the following content:

Section "Device"
        Identifier  "card0"
        Driver      "intel"
        Option      "Backlight"  "intel_backlight"
        BusID       "PCI:0:2:0"


Log out to see if it works.

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protected by Community Jan 17 '14 at 16:11

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