Can you please help me ?

I tried everything I found and nothing worked. For example, I modified grub configuration file, installed xbacklight and tried setpci command.

  • It looks like I have the same problem. Actually the nvidia settings allow to alter the brightness of the display. However I suspect that not the backlight is altered but the pixel colors. Thus I assume that it is not possible to save power by reducing brightness this way.
    – user64908
    May 20, 2012 at 17:47
  • Have any of the answers resolved your problem?
    – belacqua
    Jun 11, 2012 at 14:32
  • Try installing display drivers: askubuntu.com/questions/247145/…
    – user142877
    Mar 24, 2013 at 6:25

4 Answers 4


Your best bet would be to reference this post, while it doesn't reference your exact machine many users have used this patch to fix their screen brightness problems. If you are starting to wonder about Toshiba Satellite backlit keys as well (just taking a jump here), its a known bug; and it has been flagged with a low priority by Canonical.

  • Thanks for answering ! When I press FN+F6 and FN+F7, nothing happens at all. In System Settings/Screen, when I try to move the brightness bar, same result : nothing. I tried keks-n's solution but it didn't work :(
    – user52401
    Mar 28, 2012 at 6:57

Type su and enter root password in terminal

And then type this :

echo "x" > /sys/class/backlight/acpi_video0/brightness

where x = 0 - 7


-If use nVidia just open dash home and type "NVIDIA X server setting",

-Then click "X Server Color Correction" under X Screen O,

-Reduce the Brightness level,

-Click "Confirm current changes" before the time runs out,

-Choose Quit to save the change.

It worked for me with the following spesifications:

Toshiba Satellite L745

Intel Core i3

NVidia GeForce with CUDA



I had the same issue on my Toshiba satellite L755. The new Nvidia driver v331.38 solved the problem. Now hibernation, sleep and fn keys for brightness work fine. Ubuntu 14.04LTS.

  • Could you please expand your answer detailing how to install the driver? Oct 22, 2014 at 8:11

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