Today, I want to share a quick trick to anybody who have a problem with brightness buttons in Kubuntu Gutsy. The problem is known when you press Fn + Home (End) to adjust screen brightness in a Lenovo Thinkpad computer using Ubuntu Linux. You think that your screen will be darker or brighter but it doesn't work. There are a lot of questions about this bug on Ubuntu forum. So, if you have not yet found a proper answer may be this is a solution for you.

Open file:

vim /etc/acpi/thinkpad-brightness-up.sh
Add this line before "exit"
echo 4 > /proc/acpi/ibm/cmos
Open another file:
vim /etc/acpi/thinkpad-brightness-down.sh
Also insert this line before "exit"
echo 5 > /proc/acpi/ibm/cmos
Hopefully the problem will be fixed in your case.

21 comments

  1. Topendharness // 12/30/07, 8:28 AM  

    I use an IBM Thinkpad R40 and the buttons work fine on my Kubuntu 'gutsy' installation without any tinkering!

  2. VnTutor // 12/30/07, 1:43 PM  

    Thanks for your comments. I think Kubuntu also works on other models as well. But the problem is found on Lenovo T61.

    If you use this hack successfully on other models (e.g. Toshiba, HP, Dell), please leave your notes here. Your messages will help Ubuntu friends to save time.

  3. Etienne // 12/31/07, 9:14 PM  

    On a Lenovo R61, this hack doesn't work.
    Doing a echo > 5 or 4 manually worked, only in console mode (Ctrl-Alt-1).

  4. VnTutor // 1/1/08, 7:59 PM  

    I will show you the content of files on my case.

    the first one: /etc/acpi/thinkpad-brightness-up.sh


    #!/bin/bash
    manufacturer=`dmidecode --string system-manufacturer`
    case "$manufacturer" in
    LENOVO*)
    echo 4 > /proc/acpi/ibm/cmos
    exit
    ;;
    *)
    . /usr/share/acpi-support/key-constants
    acpi_fakekey $KEY_BRIGHTNESSUP
    ;;
    esac

    the second one: /etc/acpi/thinkpad-brightness-down.sh

    #!/bin/bash
    manufacturer=`dmidecode --string system-manufacturer`
    case "$manufacturer" in
    LENOVO*)
    echo 5 > /proc/acpi/ibm/cmos
    exit
    ;;
    *)
    . /usr/share/acpi-support/key-constants
    acpi_fakekey $KEY_BRIGHTNESSDOWN
    ;;
    esac

    Please make a comparison with your files.

  5. Etienne // 1/3/08, 12:59 AM  

    Hi,

    the contents of the files are the same. My OS is Ubuntu 7.10.

    Thanks.

  6. VnTutor // 1/3/08, 11:01 AM  

    I think it should work well with Ubuntu 7.10. I just see this problem in Kubuntu 7.10 after I have installed on Lenovo T61.

  7. sandia // 1/5/08, 12:02 AM  

    I tried it in Ubuntu 7.10 with my Lenovo T61 and my buttons are still not working. Did you have to do some extra stuff after changing the files?

  8. VnTutor // 1/5/08, 4:03 AM  

    You try these commands to change (up or down) 10% Brightness of your current screen.

    dcop `dcop | grep power-manager` power-manager brightnessUp

    dcop `dcop | grep power-manager` power-manager brightnessDown

  9. ryanm2215 // 1/10/08, 11:26 AM  

    thanks, fix worked perfectly first try on my x60s.

  10. Anonymous // 1/17/08, 12:48 AM  

    Hey,
    this fix works perfectly on a T60 running Kubuntu 7.10.

    Thanks.

  11. Anonymous // 1/18/08, 10:45 PM  

    Does NOT work as-is on a Dell Inspiron 9400, Kubuntu Gutsy.

  12. chanapong // 4/7/08, 10:15 AM  
  13. XiR_ // 4/24/08, 6:04 PM  

    It has worked OK on a lenovo R61. Thank you

  14. yclian // 1/31/09, 8:06 PM  

    I used to use /proc/acpi/video/VID/LCD0/brightness to change my brightness but it doesn't seem working anymore for god-knows-why reason.

    Your solution works for me now, thanks a lot!

    yc

  15. Anonymous // 2/19/09, 10:56 AM  

    It works on my Thinkpad X61, thanks.
    What actually happens when I say echo 4 > /proc/acpi/ibm/cmos ?

  16. Anonymous // 3/5/09, 9:06 AM  

    fix worked perfectly on first try with lenovo x61

  17. nickel // 3/25/09, 7:20 PM  

    Restored on lenovo R61 - Ubuntu 8.10 Intrepid Ibex

    Saved my eyesight!

  18. janus // 3/27/09, 10:50 AM  

    on a x61s with kubuntu 8.10 this worked perfectly :) thank you

  19. Anonymous // 3/27/09, 4:32 PM  

    That did it!! Thanks

  20. Anonymous // 5/17/09, 2:33 AM  

    Great, I'd never been able to adjust the brightness on my r61e. I can confirm that this works for Jaunty.

    Thanks,
    -Ian

  21. Anonymous // 6/8/09, 6:21 PM  

    Thanks a lot! This really saves my Thinkpad under ubuntu