I've just installed Ubuntu 16.04 on my Lenovo Z400 notebook and everything was working. Today I tried to change the brightness of the screen and it gets dark and I can't go back. Can anyone help me?



1 Answer 1


I faced the same problem before on my laptop Lenovo z500 ideapad after searching i found this solution :

  1. open terminal
  2. sudo nano "/etc/default/grub"
  3. append acpi_backlight=vendor to the GRUB_CMDLINE_LINUX_DEFAULT line:

    GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
  4. save and close nano (Ctrl+X, then confirm saving changes)
  5. sudo update-grub
  6. restart

If nothing changes , you can check the solutions of this question.

  • This does not work for ThinkPad P50 on 17.10. Commented Feb 8, 2018 at 10:05
  • this did not work. (Lenovo Ideapad). Commented Nov 22, 2021 at 10:34

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