Can't change brightness with keyboard or with "Brightness and Lock" settings panel

Bug #947919 reported by Matthew Paul Thomas on 2012-03-06
This bug affects 5 people
Affects Status Importance Assigned to Milestone
Fix Released
gnome-desktop3 (Ubuntu)
mutter (Ubuntu)

Bug Description

gnome-settings-daemon 3.3.91-0ubuntu1, gnome-control-center 1:3.3.90-0ubuntu5, Ubuntu 12.04 beta

1. Press the Brightness keys on the keyboard.
2. In System Settings, click "Brightness and Lock".

What happens:
1. Nothing.
2. The "Brightness and Lock" panel does not contain any brightness settings.

What should happen:
1. The brightness changes.
2. The "Brightness and Lock" panel contains a brightness slider.

Matthew Paul Thomas (mpt) wrote :
Matthew Paul Thomas (mpt) wrote :

Thanks to Andrea Cimitan for enlightening me that this is not a problem with the design of the panel. The brightness keys on the keyboard are not working either, whereas they worked yesterday. However, xbacklight works to change the brightness, so I guess it's not a problem with the graphics driver. Moving to gnome-settings-daemon.

affects: gnome-control-center (Ubuntu) → gnome-settings-daemon (Ubuntu)
description: updated
summary: - "Brightness and Lock" doesn't contain any brightness settings
+ Can't change brightness with keyboard or with "Brightness and Lock"
+ settings panel
Amigo Tuyo (rafael-ensenyat) wrote :

I have this same problem and I couldn't find any solution so far. Also, xbacklight seems no to work for me. I'm new to ubuntu and I feel kinda lost here...

Launchpad Janitor (janitor) wrote :

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

Changed in gnome-settings-daemon (Ubuntu):
status: New → Confirmed
Dana Goyette (danagoyette) wrote :

In my case, I'm using an nvidia card on a Thinkpad, with EnableBrightnessControl set.

On at least the Intel driver, xrandr --verbose presents both 'BACKLIGHT' and 'Backlight'.
The nvidia driver (with EnableBrightnessControl set) offers only the latter.

libgnome-desktop (used by gnome-settings-daemon) seems to look for only the former.
xbacklight looks for both names; this must be why it works when Gnome does not.

That other bug report (#947748) has several different issues lumped into it.
I'd like to remove the "duplicate" flag, since this report mentions the xbacklight behavior.

Changed in gnome-settings-daemon (Ubuntu):
status: Confirmed → Triaged
importance: Undecided → Medium
tags: added: ubuntu-desktop-trusty
Robert Ancell (robert-ancell) wrote :

According to the XRANDR spec [1] the correct property is "Backlight".


affects: gnome-settings-daemon (Ubuntu) → gnome-desktop3 (Ubuntu)
Robert Ancell (robert-ancell) wrote :

The upstream code for this moved into Mutter.

Changed in mutter (Ubuntu):
status: New → Triaged
importance: Undecided → Medium
Robert Ancell (robert-ancell) wrote :

I suspect this bug is not frequently seen since gnome-settings-daemon falls back to using /sys/class/backlight if XRANDR doesn't provide a backlight setting.

Changed in mutter:
importance: Unknown → Medium
status: Unknown → New
Changed in mutter:
status: New → Fix Released
Tim Lunn (darkxst) on 2014-02-06
Changed in mutter (Ubuntu):
assignee: nobody → Tim (darkxst)
Tim Lunn (darkxst) on 2014-02-06
Changed in mutter (Ubuntu):
assignee: Tim (darkxst) → nobody
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package mutter - 3.10.3-0ubuntu3

mutter (3.10.3-0ubuntu3) trusty; urgency=medium

  * debian/patches:
    - remove unused git patches
    - git_fix_xrandr_backlight.patch, fix backlight not working on various
      GPU's (LP: #947919)
 -- Tim Lunn <email address hidden> Thu, 06 Feb 2014 20:01:34 +1100

Changed in mutter (Ubuntu):
status: Triaged → Fix Released
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package gnome-desktop3 - 3.8.4-0ubuntu3

gnome-desktop3 (3.8.4-0ubuntu3) trusty; urgency=medium

  * debian/patches/backlight-property-name.patch:
    - Use the corrent backlight property name as specified in the XRANDR spec
      (LP: #947919)
 -- Robert Ancell <email address hidden> Mon, 17 Mar 2014 17:28:55 +1300

Changed in gnome-desktop3 (Ubuntu):
status: Triaged → Fix Released
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