Results 1 to 4 of 4

Thread: Brightness controls on Ubuntu 13.10 and Dell Latitude 15 3000

  1. #1
    Join Date
    Jan 2014
    Beans
    3

    Brightness controls on Ubuntu 13.10 and Dell Latitude 15 3000

    Hi Folks,

    I've recently acquired a new Dell Latitude 15 3000 series, and have replaced the bundled Windows 8.1 install with Ubuntu 13.10 (x86) on it. All is working incredibly well, but for the display brightness controls. Neither the hardware function keys or the Brightness slider control under Ubuntu System Settings have any effect on display brightness, even though the OSD registers hardware key presses in the case of the former.

    I see from other forum posts and general searches on the web that this is a common problem that seems to afflict Ubuntu 13.10 in particular. I've tried a couple of the common recommended fixes which worked for other people but in my case they do not resolve the issue. Specifically, I attempted both of the workarounds at http://askubuntu.com/questions/36315...d-edge-lr236w5 with no change in behaviour.

    Following is some system information I've gleaned from other posts:

    Code:
    lspci -k | grep -iA2 VGA
    00:02.0 VGA compatible controller: Intel Corporation Haswell-ULT Integrated Graphics Controller (rev 09)
        Subsystem: Dell Device 0608
        Kernel driver in use: i915

    Code:
    for i in /sys/class/backlight/*; do echo $i; cat $i/brightness; cat $i/actual_brightness; cat $i/max_brightness; done
    /sys/class/backlight/acpi_video0
    99
    99
    99
    /sys/class/backlight/intel_backlight
    110
    110
    937

    It would be awesome if one of the experts could please give me a hand with resolving this remaining problem if possible

    Cheers,
    Dave

  2. #2
    Join Date
    Jun 2005
    Location
    Toronto, Canada
    Beans
    Hidden!
    Distro
    Xubuntu 16.04 Xenial Xerus

    Re: Brightness controls on Ubuntu 13.10 and Dell Latitude 15 3000

    Hello and welcome to the forums.

    Can you give the following a try? It will force the system to use the intel_backlight interface as the main backlight interface.

    1. Create the /usr/share/X11/xorg.conf.d/20-intel.conf file with root privlidges (from a terminal window):
    Code:
    sudo -i gedit /usr/share/X11/xorg.conf.d/20-intel.conf
    2. Copy/paste the following code:
    Code:
    Section "Device"
            Identifier  "card0"
            Driver      "intel"
            Option      "Backlight"  "intel_backlight"
            BusID       "PCI:0:2:0"
    EndSection
    3. Save the file.

    4. Log out and back in again to test.



    Note: If you have any problems logging back in, simply go to the first virtual console by pressing Ctrl+Alt+F1, login to that console and delete the file you created:
    Code:
    sudo rm /usr/share/X11/xorg.conf.d/20-intel.conf
    ...and restart your computer:
    Code:
    sudo reboot

  3. #3
    Join Date
    Jan 2014
    Beans
    3

    Re: Brightness controls on Ubuntu 13.10 and Dell Latitude 15 3000

    Hi Toz,

    Thanks for your help - that did the trick!

    Cheers,
    Dave

  4. #4
    Join Date
    Jan 2014
    Beans
    3

    Re: Brightness controls on Ubuntu 13.10 and Dell Latitude 15 3000

    Hi Toz/All,

    Actually there is one small remaining quirk - post-reboot the brightness level is reset to about 1/5th total brightness (this is without the power supply plugged in by the way). The controls will continue to function however. Is there a way of setting the default brightness level or otherwise forcing the last-set brightness level to be remembered through a reboot?

    [EDIT] - this appears to be normal behaviour without A/C power (while charging it will default to full brightness), so please ignore my last question - thanks again for your help.
    Last edited by davekoelmeyer-b; January 10th, 2014 at 02:40 AM.

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •