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Intel HD3000 problem with brightness function keys - Dell N411z

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01 Staff's picture
Starter
01 Staff (not verified)

May 12, 2014 - 08:07am

  • 01 Staff's picture
    01 Staff (not verified)

    Hi all.

    To cut the long story short, the brightness keys in my Dell n411z were working just fine up to version 13.04 of ubuntu.

    I don't know what has changed after this release, but on 13.10 and 14.04 the brightness functions keys (Fn+F4 and Fn+F5) do not work. It's like the are dead. They do not produce any results.

    More info about this can be found on this bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1229591

     

    Does this have anything to do with the intel graphics drivers...?

    May 12, 2014 - 08:07am
  • fledermaus's picture
    fledermaus (not verified)

    Hard to say without access to the machine: Could be a regression in whatever bit of
    unity handles those keys, or it's possible you need to boot your kernel with the "nomodeset"
    option or similar added to the kernel command line.

    May 16, 2014 - 09:50am
  • jeremyb's picture
    jeremyb (not verified)

    Booting kernel with option- acpi_backlight=vendor

    might fix it

    May 16, 2014 - 11:11am
  • madvinegar's picture
    madvinegar (not verified)

    I have tried all sorts of boot parameters... None of them works.

    Just to be clear, the brightness adjustment works juts fine. I can adjust same via settings. It's the keys that do not work.

    The strange thing is that the brightness buttons were working right out of the box till kernel 3.8. On kernels 3.11 and 3.13 they do not work. It's like they are dead...

     

    It's a kernel thing? I don't know... I really wish they fix it.

    May 17, 2014 - 01:23pm
  • jeremyb's picture
    jeremyb (not verified)

    please try

    cat /var/log/Xorg.0.log | grep backlight

    in terminal and post the output

    May 17, 2014 - 04:38pm
  • jeremyb's picture
    jeremyb (not verified)

    And another

    for interface in /sys/class/backlight/*; do echo $interface; cat $interface/max_brightness; done

    May 17, 2014 - 04:44pm
  • madvinegar's picture
    madvinegar (not verified)

    The results:

    mike@Linux-Dell:~$ cat /var/log/Xorg.0.log | grep backlight
    [    25.683] (--) intel(0): found backlight control interface acpi_video0 (type 'firmware')

    mike@Linux-Dell:~$ cat /sys/class/backlight/acpi_video0/max_brightness
    16



     

     

     

    May 17, 2014 - 11:49pm
  • madvinegar's picture
    madvinegar (not verified)

    I post them again:

     

    mike@Linux-Dell:~$ cat /var/log/Xorg.0.log | grep backlight
    [    25.683] (--) intel(0): found backlight control interface acpi_video0 (type 'firmware')


    mike@Linux-Dell:~$ cat /sys/class/backlight/acpi_video0/max_brightness
    16
    mike@Linux-Dell:~$
     

    May 17, 2014 - 11:50pm
  • madvinegar's picture
    madvinegar (not verified)

    There are two interfaces inside /sys/class/backlight:

    mike@Linux-Dell:~$ echo /sys/class/backlight/*
    /sys/class/backlight/acpi_video0 /sys/class/backlight/intel_backlight
     

    and:

    mike@Linux-Dell:~$ cat /sys/class/backlight/intel_backlight/max_brightness
    4882
     

    May 17, 2014 - 11:53pm
  • madvinegar's picture
    madvinegar (not verified)

    jeremyB first of all thanx for your email.

    I tried your suggestions, the backlight changes just fine using the terminal commands for both cards (intel_backlight and acpi_video0). However, unfortunately the brightness function keys are dead.

    I also created the 20-intel.conf, and again I tried both cards, rebooted but still the functions keys do not work.

     

    As I said, I can adjust the brigthness just fine by using terminal or the slider in brightness settings.

    The only problem is the brightness functions keys that are dead and do not even produce evdev results!

    And these keys worked just fine right out of the box till ubuntu 13.04.

    They do not work in 13.10 and 14.04.

     

    If you read in my first post the link for the bug, they have narrowed it down to 3.11.0-0.2 as the start of the problem. The last working saucy kernel was 3.10.0-6.17.

    May 18, 2014 - 02:41pm
  • madvinegar's picture
    madvinegar (not verified)

    Just another piece of information I would like to add.
    As I said, I have ubuntu 14.04 installed with kernel 3.13.

    I have downloaded from here: http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.2.59-precise/ the latest 3.2 kernel and installed it.
    More specifically I downloaded and installed the following 3 packages:

    linux-headers-3.2.59-030259-generic_3.2.59-030259.201405181035_amd64.deb
    linux-headers-3.2.59-030259_3.2.59-030259.201405181035_all.deb
    linux-image-3.2.59-030259-generic_3.2.59-030259.201405181035_amd64.deb

    I rebooted and then booted with kernel 3.2.
    So my system was 14.04 but with kernel 3.2.

    Much to my surprise the brightness function keys did NOT work !!! (all the other function keys worked).
    I booted a live USB with ubuntu 12.04 (kernel 3.2) and the brightness keys worked just fine.

    So, is it NOT a kernel thing? Is it something else??? What could it be...????

     

    May 21, 2014 - 10:36am