The slider does not change the brightness

[AlexLomax]

Hello.
I am tryed to use live cd Ubuntu 13.04 daily build on my eMachines E525 laptop.
When I open the "Brightness and lock" and try to change the brightness using the slider, the brightness does not change.
I use the "acpi_osi=Linux acpi_backlight=vendor" options in "/etc/default/grub"

[AlexLomax (alex-lomtev-deactivatedaccount)]

Apport log.

[AlexLomax (alex-lomtev-deactivatedaccount)]

I learned that the gsd-backlight-helper is trying to change the brightness in

/sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0/brightness

but it does not work. I can change the brightness only by

/sys/class/backlight/intel_backlight/brightness.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[AlexLomax (alex-lomtev-deactivatedaccount)]

In saucy this bug still persist (3.8 kernel) , but in precise it works (3.2 kernel).

[AlexLomax (alex-lomtev-deactivatedaccount)]

Today I installed Elementary OS Luna 0.2 with 3.2 kernel - a slider worked perfectly. Then I installed linux-image-generic-lts-raring (3.8 kernel) and xserver-xorg-lts-raring, then the slider stopped working. Maybe the problem is xorg or video driver?

[AlexLomax (alex-lomtev-deactivatedaccount)]

Create a file /etc/X11/xorg.conf.d/20-intel.conf with the following content:

Section "Device"
        Identifier "HD 4000"
        Driver "Intel"
        Option "Backlight" "intel_backlight"
EndSection

All works fine!

[Sebastien Bacher (seb128)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. The issue you are reporting is an upstream one and it would be nice if somebody having it could send the bug to the developers of the software by following the instructions at https://wiki.ubuntu.com/Bugs/Upstream/GNOME. If you have done so, please tell us the number of the upstream bug (or the link), so we can add a bugwatch that will inform us about its status. Thanks in advance.