I have installed Ubuntu 13.04 on Lenovo G700 Laptop.

  1. Screen backlight is going off after boot.

  2. I have tried to fix it with setting

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
    in /etc/default/grub file - in that case backlight is set up to 100% and I am not able to change it.

I am looking for a solution when screen is not black after boot and I am able to change the backlight.


I used following settings

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"

Backlight after boot is set to 100% and I am able to change it with System Settings or hardware keys.


Try this instead

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

also make sure you run

sudo update-grub

before you reboot

  • Also use the FN keys to change brightness or set a key binding for it, because sliders still refuse to work even with a fix like this. – Lemagex Sep 24 '13 at 17:17
  • I have tried your solution. Screen backlight after boot is set to 100% lighten - I am able to change it with "System settings" but not with hardware keys. – Paweł Łabaj Sep 25 '13 at 23:07
  • That's as far as my knowledge with backlight fixes in grub goes, sorry, I wish I could help further. – Lemagex Sep 27 '13 at 6:24

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