Ubuntu fix Fn Brightness keys

So my Acer Aspire 5738 encountered the oh-the-Brightness-Function-keys-are-not-working-yet-again issue after the installation of Ubuntu 12.04. There is a simple fix and some related caveats. So here we go …..

#1 (open the file in gedit or vi)

$ sudo vi /etc/default/grub
[sudo] password for nikunj:

#2 (find an insert the arguments in gray)

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=Linux acpi_backlight=vendor

#3 (update the grub configuration)

$ sudo update-grub
Generating grub.cfg …
Found linux image: /boot/vmlinuz-3.2.0-24-generic
Found initrd image: /boot/initrd.img-3.2.0-24-generic
Found linux image: /boot/vmlinuz-3.2.0-23-generic
Found initrd image: /boot/initrd.img-3.2.0-23-generic
Found memtest86+ image: /boot/memtest86+.bin
Found Windows 7 (loader) on /dev/sda1
Found Ubuntu 11.10 (11.10) on /dev/sda2

Just reboot the machine.


At times the screen would go entirely dark. Or would not apparently resume from a blank screen or when the screensaver gets active.

For such cases, all you need to do is press “Fn + Brightness UP button” and screen will GLOW. Simple!!

(This post is more like a NOTE TO SELF. But if it helps you in someway then its even better … AWESOME!! :D)


Works for Ubuntu 12.10 perfectly 🙂

Update (2013/01/08):

You can use “sudo gedit /etc/default/grub” if you are not very familiar with vi editor! 🙂

Update (2013/05/12):

For Ubuntu 13.04 do the following:

GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=Linux acpi_backlight=vendor

Update (2014/05/25):

Works on Ubuntu 14.04.

130 thoughts on “Ubuntu fix Fn Brightness keys

      • I just installed ubuntu 12.04 on my AOD270 (Acer Aspire One) notebook. Your fix brightened the screen, but also put suspend and resume/awake in order. Before, after a suspend the screen would just be a coloured mass of things and I had to switch off the computer and reboot manually.
        Thank you.

  1. Dude… Thanks a lot bro as this fixed it.. This’s the beauty of using Ubuntu… Sure one runs into problems but with time, the solution can be found with the online community..I have an Acer Aspire V3-471G and have wireless disconnecting issues… I’d appreciate if u can help or point me in the right direction.. Thanks again.

    • I am 🙂 so glad that you made an effort to write a note (and this post helped you).

      As our beloved Acer people do not make any effort to release drivers for Unix, the community has to contrive and provide.

      Let’s try it the way I used to make it work back at college…
      Heard: ndiswrapper??

      It is mostly bundled on the Ubuntu CD, if its not already installed. You just need to give it the INF file path of your Windows XP Wifi drivers…and it creates a brand new module for Linux (after parsing that driver info), so that you can use it to connect to the internet. Try it. It should help. 🙂 or Google the problem with “Ubuntu And Acer model number”.
      Do Let me know.

  2. Pingback: Pengalaman Penggunaan Ubuntu 12.04 dan Troubleshootingnya + Bonus :) « IKONspirasi

  3. thanks Nikunj Lahoti 🙂 this problem was a headache for long time for me! simple solution but brilliant.

  4. acer aspire one, ubuntu 12.04, the fn key has no effect, some of the keys work without using fn but are still shuffled, messed up. like the wireless key isn’t working and I need it.

  5. mine is acer aspire one D257, dual boot win7 and ubuntu. Not working, fn key not working as it was initially, some of the keys work but are shuffled. This was after a normal ubuntu update. before that it was perfect

      • Yeah, I figured acer service center changed my motherboard, the notebook had a problem and i took it for repair, its a bios issue the keys are just shuffled and fn works in reverse. I have to press fn to use f5 for refresh, for example… anyway, this hack helped in the first place.

    • Cool! That’s interesting. You must have gotten used it by now. Its like you have the third SHIFT button. Tough luck! Write a post about it 🙂 It would be legendary!

  6. Pingback: texens » [Solution] Brightness not working on Ubuntu 12.04 LTS

  7. hey mine is acer aspire 5750
    before applying your solution:Fn slider for brightness moved but brightness did not reduced
    after applying:brightness slider is absent now..what to do..plz reply

    • Oh that’s strange.
      Undo it. And see if the slider is back. Otherwise we did not do it correctly.
      And also I will try to find out what is the common factor in the people for who this is working. Let me get back to you!

      • Hi Nikunj Lahoti I have an acer aspire 7741 with win7 and I wouldlike to install ubuntu 12.04 and the problem is when I start the install from ubuntu cd the backlight is directly set to minimum and I cannot makes any action because the screen is black (brightness set to min) Did you already see this case ?

      • Well that’s new.
        I think there are two things that you can do.
        A) try 12.10 instead of 12.04 (they might have fixed it already)
        B) when you live boot into Ubuntu, and see the boot screen (GRUB) press ‘e’ and edit the command-line abs insert the text mentioned in the post above 🙂
        Let me know if your can fix it. Otherwise we can retry tonight or maybe on Sunday (in office right now & they have switched off the air conditioning 😦 …)!

    • That it does. Also try a gray or black theme for Ubuntu.
      For the browser extensions/plugins look at my post “Blank your monitor”!

      & of course reducing your screen time is important.

    • Hello there. For some WordPress UI bug this is the third time that I am writing this note 😦 I am now going to use clipboard.

      Login as “root” and then try to perform the actions.
      My guess is – you couldn’t use “sudo” and are running the commands as an unprivileged user.

      If #1 doesn’t work then perhaps you have LILO installed. Use http://wiki.mandriva.com/en/Drakboot_–boot and ask your OS to use GRUB instead. Then proceed normally!

      Keep experimenting!

    • Hi! Can you please login as root (or maybe just `sudo gedit /boot/grub/grub.cfg`) to edit /boot/grub/grub.cfg and append the string “acpi_backlight=vendor” to the lines starting with “linux /boot/vmlinuz”?
      That’s it! Reboot your machine. Let me know!

  8. i’m on ubuntu 12.10
    i’ve updated grub and even edited the text
    the problem now is dat i cant increase my brightness
    and whenevr i reboot i find my screen bright to the most
    PLEASE help ME

  9. Hello, I have a laptop acer ASPIRE 5733-6604 with UBUNTU 12.10 on it running perfectly, but my brightness function is not working, it is always fully bright, it doesn’t decreases when I push the buttons… I found your page and tried to use the commands, but when I try to change the line, it’s not like how you said, I can’t erase the final quotation marks and the line appears like this
    GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash”acpi_backlight=vendor“
    Every time I try to erase that damn extra quotation mark I fill the screen with Ds or Cs and it doesn’t even let me update the grub… I’m so frustrated because I don’t know how to fix it because I don’t understand a thing about these kind of things using commands and stuff…
    What do I need to do? Could you explain a bit more slowly to me?

    • Hello there 🙂
      It’s so good to hear from you.
      This is my fault actually. Everyone doesn’t know `vi` editor that well. Tell you what.. open the terminal and write without quotes:
      “sudo gedit /etc/default/grub”
      Just put in the password and you should be good to go.

      So essentially you are using a visual editor instead of a command line one to achieve this.

      Please keep asking questions and happy hacking 😀

      And if you still want to know how it’s done in `vi`, open the file and press ESC. Navigate using arrow keys to that place where you wish to insert the text. Press “i” for insert (Do not use arrow keys now that you are in insert mode). Paste or write it down. When you are done press ESC (to go back to command mode). And say “:” immediately with “x” to save it (In this mode if you need to remove something then just go to that character and type “x”)

      Vi is very very powerful. It grows on you 🙂


  10. thanks a lot 🙂
    worked for my Lenovo G580 as well
    why dont they care about releasing drivers for the linux platform?
    thanks again!

  11. hi i m new on linux. pls help me to solve brightness control on my lenovo g580. give me easy and full instraction. m new…

    • Hey Abhijit! Please go ahead and follow the steps one after another. If you feel stuck then reply here with the error message that you see. I will try to help you with that.

  12. thanks Nikunj for this post. I was able to solve the issue on my Lenovo laptop. But I could do it only after you explained it further in reply to a comment by user Morgan. For first time ubuntu users, it helps to have easy and detailed step by step instructions.

    All the best

  13. Hi Nikunj. After change the setting “quiet splash acpi_backlight=vendor”, the brightness can adjust. Thanks.
    But after I change the brightness to minimum with Fn, the LCD will be black. I can’t see anything on screen. How about you?

    By the way, I update the Ubuntu from 12.04 to 12.10. There is the same issue.

    • Yes that’s a known issue 🙂
      But has its applications as well (think: conserve battery)

      Each time you upgrade, the bootloader configuration is changed. So you would have to redo it. Btw 13.04 is going to be out in a few days so wait for it 😀

  14. Thanks Nikunj. Working well for me on Acer Aspire V3-471G.
    There is one observation. Default brightness is full even after adjusting it to 50% in System Setting. Not irritating as I adjust it with keys after booting.

    • Sure thing. Can you please execute this in a terminal (without the dollar)

      $ sudo gedit /etc/default/grub

      And check that step two has been done correctly? Also paste the contents here if it still doesn’t work.

      * do read the comments above. It’s working for people using the same laptop model.

      • I just follow the second step, and add the string on GRUB_CMDLINE_LINUX_DEFAULT.
        Here my grub file:

        # If you change this file, run ‘update-grub’ afterwards to update
        # /boot/grub/grub.cfg.
        # For full documentation of the options in this file, see:
        # info -f grub -n ‘Simple configuration’

        GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
        GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_backlight=vendor”

        # Uncomment to enable BadRAM filtering, modify to suit your needs
        # This works with Linux (no patch required) and with any kernel that obtains
        # the memory map information from GRUB (GNU Mach, kernel of FreeBSD …)

        # Uncomment to disable graphical terminal (grub-pc only)

        # The resolution used on graphical terminal
        # note that you can use only modes which your graphic card supports via VBE
        # you can see them in real GRUB with the command `vbeinfo’

        # Uncomment if you don’t want GRUB to pass “root=UUID=xxx” parameter to Linux

        # Uncomment to disable generation of recovery mode menu entries

        # Uncomment to get a beep at grub start
        #GRUB_INIT_TUNE=”480 440 1″

        Yes, some lenovo user work with this way.. Is it because i use LXDE and the key still won’t work.?

    • So you should create shell scripts to modify the brightness. Later bind those key combinations to the two scripts (one to increase the brightness and the other one to decrease :))

  15. Satish says:
    April 13, 2013 at 12:21

    Thanks Nikunj. Working well for me on Acer Aspire V3-471G.
    There is one observation. Default brightness is full even after adjusting it to 50% in System Setting. Not irritating as I adjust it with keys after booting.

    Nikunj Lahoti says:
    April 14, 2013 at 01:01

    🙂 bravo! You can put the command to modify brightness in a shell script and run that on system startup (think: bash profile etc)


    This worked for me — http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart

      • The brightness is stuck at around 90-100% when i try editing brightness under power settings.(screen brightness) nothing happens, moving it up and down has no result.

        I’d like to change it to have better battery life. Sorry for the noob question i’m new to linux =D.

        I might try gnome out as i’m not that found of unity either.

  16. @Victor Crane: I had the same problems with frequent wifi disconnections what made working over a VPN connection very frustrating. However, the update to 13.04 fixed that! Apparently, because of the new Kernel version. So if you haven’t already, go and update!

    @Nikunj: THANKS! You made my day!

  17. Pingback: Fényerőbillentyűk Ubuntu 12.04 alatt | Ariszló

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  19. Pingback: The pragmatical Jerônimo » Fix brightness trouble on acer notebooks using linux

  20. hey me using ubuntu 13.04.. i also have brightness issue in it.
    i used following commands:-
    sudo -H gedit /etc/default/grub
    GRUB_CMDLINE_LINUX_DEFAULT=GRUB_CMDLINE_LINUX=”quiet splash acpi_osi=Linux acpi_backlight=vendor”

    and then update file using:-
    sudo update-grub

    but it does’nt work at all. so plzz help

    • Hey Manisha, look at a recent comment from Geronimo:

      $ sudo sed -i ‘s/GRUB_CMDLINE_LINUX_DEFAULT.*/GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=Linux acpi_backlight=vendor”/’ /etc/default/grub

      # Now update grub. Let me know if it doesn’t work for you.

  21. Ey muchas gracias, funcionó perfecto para xubuntu 14.04 sobre un acer aspire v3-471-666 1

    😀 thank you very much, worked perfect for xubuntu 14.04 on a acer aspire v3-471-6661

  22. it’a one abnormal behaviour on asus eeepc notebook wtih Fn brightness keys on ubuntu 14.04. when you press Fn+F5, or Fn+F6 keys to change brightness, brightness jumps twice or three times. it’s said about, it’s a matter of performing brightness change forst by acpi and after that Xserver, so result is, brightness changes faster, in larger steps than you like. for me have worked one slighlty different solution, change line at /etc/default/ grub as Nikunj suggests on the begining, but insted of acpi_backlight=vendor use acpi_backlight=off
    this will cause, brighness change information slider doesn’t appear as before, but brightness changes in normal, bios supported step, it seems to me it’ 10 steps. have a nice days guys.

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