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Thread: help : brightness control

  1. #11
    Join Date
    Nov 2007
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    15

    Re: help : brightness control

    $: cat /proc/cmdline

    BOOT_IMAGE=/boot/vmlinuz-3.0.0-12-generic root=UUID=450425e4-b41a-441e-9d3e-1af04189e5a2 ro quiet splash vt.handoff=7


    $; /sys/class/backlight

    acpi_video0 intel_backlight

  2. #12
    Join Date
    May 2010
    Location
    uk
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    Xubuntu 14.04 Trusty Tahr

    Re: help : brightness control

    Hi

    Sorry. Please repeat the commands in my last post #10 but instead of using ...

    Code:
    sudo updategrub
    please use

    Code:
    sudo update-grub
    I have a sticky keyboard that needs cleaning

    I have edited post #10

    Kind regards
    Last edited by matt_symes; October 22nd, 2011 at 02:21 PM.
    If you believe everything you read, you better not read. ~ Japanese Proverb

    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

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  3. #13
    Join Date
    Nov 2007
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    15

    Re: help : brightness control

    hi matt_symes, thanks... its working...great effort ....thanks again...

  4. #14
    Join Date
    May 2010
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    uk
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    Xubuntu 14.04 Trusty Tahr

    Re: help : brightness control

    Hi

    Your welcome . Please could you mark this thread as solved.

    Kind regards
    If you believe everything you read, you better not read. ~ Japanese Proverb

    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

    Thinking about becoming an Ubuntu Member?

  5. #15
    Join Date
    Sep 2010
    Beans
    12

    Re: help : brightness control

    Sorry for reviving a week old topic, but I'm having a similar problem.

    My /sys/class/backlight/ contains the folders acpi_video0 and acpi_video1

    I've determined that acpi_video0 is able to change my backlight through
    sudo bash -c "echo 6 > /sys/class/backlight/acpi_video0/brightness"

    But acpi_video1 doesn't do anything

    Is there a way I can blacklist just one of them?

  6. #16
    Join Date
    Nov 2007
    Beans
    15

    Re: help : brightness control

    hi, donovan6000,

    try to run the 10 & 12 post....



    Quote Originally Posted by donovan6000 View Post
    Sorry for reviving a week old topic, but I'm having a similar problem.

    My /sys/class/backlight/ contains the folders acpi_video0 and acpi_video1

    I've determined that acpi_video0 is able to change my backlight through
    sudo bash -c "echo 6 > /sys/class/backlight/acpi_video0/brightness"

    But acpi_video1 doesn't do anything

    Is there a way I can blacklist just one of them?

  7. #17
    Join Date
    Sep 2010
    Beans
    12

    Re: help : brightness control

    I've already tried just about every solution I've come across, but none of them work.

    When I try the fix from those post my backlight just stays at 100% no matter what. And there are no files in my /sys/class/backlight folder.

  8. #18
    Join Date
    May 2010
    Location
    uk
    Beans
    9,249
    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: help : brightness control

    Hi

    Open a terminal and type

    Code:
    sudo modprobe -r video
    Post back results and also the results of

    Code:
    ls /sys/class/backlight
    Kind regards
    If you believe everything you read, you better not read. ~ Japanese Proverb

    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

    Thinking about becoming an Ubuntu Member?

  9. #19
    Join Date
    Sep 2010
    Beans
    12

    Re: help : brightness control

    After I add the lines to my /etc/default/grub file and update grub, my /sys/class/backlight folder become empty.

    Even after running modprobe -r video, the backlight remains unchangable. Do the ati drivers use a different directory for the backlight?

  10. #20
    Join Date
    May 2010
    Location
    uk
    Beans
    9,249
    Distro
    Xubuntu 14.04 Trusty Tahr

    Re: help : brightness control

    Hi

    Quote Originally Posted by donovan6000 View Post
    After I add the lines to my /etc/default/grub file and update grub, my /sys/class/backlight folder become empty.

    Even after running modprobe -r video, the backlight remains unchangable. Do the ati drivers use a different directory for the backlight?
    If your backlight folder is empty after adding the kernel command line then this means it has not loaded the backlight kernel module for your laptop.

    What is the exact make and model of your laptop ?

    Also now that the default backlight folder is empty open a terminall and type

    Code:
    sudo modprobe video
    This will reload the backlight video kernel modue. How many entries do you have in your backlight folder ?

    Does this lower your backlight brightness ?

    Code:
    echo 5 | sudo tee /sys/class/backlight/acpi_video0/brightness
    If this works then we need to find out why two video module nodes are being created.

    Kind regards
    Last edited by matt_symes; November 2nd, 2011 at 12:25 PM.
    If you believe everything you read, you better not read. ~ Japanese Proverb

    If you don't read the newspaper, you're uninformed. If you read the newspaper, you're mis-informed. - Mark Twain

    Thinking about becoming an Ubuntu Member?

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