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Thread: Unable to change brightness level with ubuntu 13.04 and Dell

  1. #1
    Join Date
    Aug 2011
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    24

    Unable to change brightness level with ubuntu 13.04 and Dell

    There was no problem with Ubuntu 12.10 but after upgrading to 13.04 I can't change the brightness level of my Dell 3721 laptop anymore. Nothing happend if I use the hardware keys or ubuntu system control. If I use the command "echo xxxx | sudo tee /sys/class/backlight/intel_backlight/brightness" display brightness will change, but its very uncomfortable to use the terminal to change the brightness level. Is there any solution to reactivate the hardware keys?

    VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09)"

  2. #2
    Join Date
    Jun 2005
    Location
    Toronto, Canada
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    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: Unable to change brightness level with ubuntu 13.04 and Dell

    Can you try the following kernel parameter (acpi_osi="!Windows 2012")? Like this (from a terminal window):

    1. Edit the grub configuration file:
      Code:
      gksu gedit /etc/default/grub
    2. Add the parameter by changing the line that reads:
      GRUB_CMDLINE_LINUX=""
      ...to read:
      Code:
      GRUB_CMDLINE_LINUX="acpi_osi=\"!Windows 2012\""
    3. Save the file
    4. Update Grub:
      Code:
      sudo update-grub
    5. Reboot and test.

  3. #3
    Join Date
    Aug 2011
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    Re: Unable to change brightness level with ubuntu 13.04 and Dell

    Thank you a lot, hardware keys are working again!

  4. #4
    Join Date
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    Xubuntu 14.04 Trusty Tahr

    Re: Unable to change brightness level with ubuntu 13.04 and Dell

    Great to hear.
    Can you mark this thread as solved by clicking on the "Edit" link in your original post, clicking on "Go Advanced' and changing the prefix to "[SOLVED]"? This way others can benefot from this solution.

  5. #5
    Join Date
    Aug 2011
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    Re: Unable to change brightness level with ubuntu 13.04 and Dell

    Hi

    I'm still having trouble with this. I've tried the above as well as the suggestions in http://ubuntuforums.org/showthread.php?t=2144815
    What is interesting is that I can't change the brightness in the System Settings either, although the screen power saver works.

    In 12.04 I had no problem. This is a Lenovo Z575 laptop if that makes a difference

    Any suggestions?

    Thanks
    Last edited by nickG4000; July 1st, 2013 at 03:34 PM.

  6. #6
    Join Date
    Jun 2005
    Location
    Toronto, Canada
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    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: Unable to change brightness level with ubuntu 13.04 and Dell

    Quote Originally Posted by nickG4000 View Post
    Hi

    I'm still having trouble with this. I've tried the above as well as the suggestions in http://ubuntuforums.org/showthread.php?t=2144815
    What is interesting is that I can't change the brightness in the System Settings either, although the screen power saver works.

    In 12.04 I had no problem. This is a Lenovo Z575 laptop if that makes a difference

    Any suggestions?

    Thanks
    Can you provide some more system information (from a terminal window):

    1. Your kernel boot line:
    Code:
    cat /proc/cmdline
    2. Your video card(s):
    Code:
    sudo lspci -vnn | grep -A12 VGA
    3. Your brightness interfaces and their values:
    Code:
    for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/max_brightness; done
    4. A copy of your dmesg log file:
    Code:
    pastebinit /var/log/dmesg
    ...and post back the link that is generated.

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