Every time I boot up Ubuntu or Mint, after choosing an OS from GRUB menu, before logging in, screen brightness is set to 0. What is the reason behind that?

I always end up manually turning on the brightness in order to see the logo and then login screen. It does not happen in other distros like Debian. I encounter this in Ubuntu 12.04, 13.10, Mint 15 and Mint 16.

computer specs: Laptop Lenovo g500; intel celeron 1005M 1.9G; RAM 4GB; integrated graphics; win8/mint16 dualboot

  • 1
    You may have to edit your /etc/rc.local file to include or modify an entry like echo 5 >/sys/class/backlight/acpi_video0/brightness in a case like this one or you may have for some reason an inappropriate acpi setting passed to a bootloader like grub in a case like that maybe. You should also include in your question the brand of your graphics card and/or computer and specify if it's a laptop, as there's also the question of the specific driver if it's not simply configuration.
    – user44370
    Nov 29, 2013 at 6:47
  • Thank You for Your comment I will check out what You said and add details into the original post
    – user53382
    Nov 29, 2013 at 14:01

1 Answer 1


Well, this is not perfect solution. But you can give it a try


EDIT: Following command will do the job ( I tested it on my Desktop. Ubuntu 13.10 )

apt-get install x11-xserver-utils
xgamma -gamma .75

Here 75 is the percentage of brightness. Please note the leading "." You can specify from 0.100 to 10.000

  • Could you copy the relevant details from that AU post to here so that this answer can stand on its own?
    – slm
    Nov 29, 2013 at 6:56
  • I tried that. 1) tried to install the package but it had been already present. 2) xgamma -gamma command set the brightness in current session only. After I restarted the machine, there was again black screen after OS selection. I should mention, it does not happen when I install OSs in virtualbox. machine is lenovo G500 win8/mint 16 dualboot
    – user53382
    Nov 29, 2013 at 13:57
  • You can mention that command in one of the startup script to get executed every time. e.g. ~/.bashrc file. For virtualBox solution, I have not tested yet. But, if xgamma is not useful the try xbacklight. Though, I am not sure about it
    – SHW
    Nov 30, 2013 at 7:08

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