I know this not a new issue concerning brightness, however, I am anxious to get this working. I added acpi_backlight=vendor to the boot parameters which allows me to change the brightness using brightness and lock but the fn + up and fn + down just turns the screen off forcing me to close the lid and reopen.

I feel like the only thing I need to do is change some values somewhere to allow these keys to change in increments, but i am not sure how. I have read of some scripts some people have wrote for other laptops, but I have not tried with mine for fear it may not work.

1 Answer 1


Did you tried this way:

step 1: terminal sudo gedit /etc/default/grub

step 2: modify your file at line GRUB_CMDLINE_LINUX="" like that: GRUB_CMDLINE_LINUX="acpi_osi=\"Windows 2012\""

step 3: terminal sudo update-grub

step 4: reboot

Worked for me on Asus X501A running Ubuntu 13.04 (same problem with fn keys)

  • Welcome to Ask Ubuntu! Please avoid posting the same answer in more than one place. When tempted to do so, typically: (1) the answer should be customized to the differences in the different questions, (2) one question should be flagged for closure as a duplicate of another (you can flag posts with 15 reputation), (3) the answer should really be a comment, or (4) the answer should be posted in the most appropriate place, and one-line comments posted on the other questions summarizing and linking to it. Jul 24, 2013 at 14:08
  • Thank you for your response! I was hoping this would finally be the solution but it does not work for me, unless I have done something wrong. I added a "!" before windows 2012 also and that did not work either. I also removed the acpi_backlight=vendor and tried it like that too and it did not work. I am open to any more suggestions, and thank you for your response!
    – user177480
    Jul 26, 2013 at 4:09

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