Brightness slider does not respond to brightness changes

[Davi da Silva Böger]

The slider in the "Brightness and Lock" settings panel does not respond to brightness changes by keyboard hotkeys.

Steps to reproduce:

1) Open "Brightness and Lock" from the control center
2) Change the brightness with the keyboard hotkeys
3) See that the brightness slider does not change

I read the similar (fixed) bug #893851 and I saw the attached patch that updated the DBus interface. Now it seems the signal is not reaching the UI for some other reason. If I run "dbus-monitor type=signal" and set the brightness up and down with the keyboard, the following output shows:

signal sender=:1.9 -> dest=org.gnome.SettingsDaemon serial=289 path=/org/gnome/SettingsDaemon/Power; interface=org.gnome.SettingsDaemon.Power.Screen; member=Changed
signal sender=:1.9 -> dest=org.gnome.SettingsDaemon serial=295 path=/org/gnome/SettingsDaemon/Power; interface=org.gnome.SettingsDaemon.Power.Screen; member=Changed

This seems to imply the signals are issued but they don't reach the UI.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: gnome-control-center 1:3.4.2-0ubuntu19
ProcVersionSignature: Ubuntu 3.5.0-17.28-generic 3.5.5
Uname: Linux 3.5.0-17-generic i686
NonfreeKernelModules: nvidia wl
ApportVersion: 2.6.1-0ubuntu3
Architecture: i386
Date: Tue Oct 23 15:22:25 2012
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
SourcePackage: gnome-control-center
UpgradeStatus: Upgraded to quantal on 2012-10-19 (4 days ago)
usr_lib_gnome-control-center:
 activity-log-manager-control-center 0.9.4-0ubuntu4
 deja-dup 24.0-0ubuntu1
 gnome-control-center-signon 0.0.18-0ubuntu1
 indicator-datetime 12.10.2-0ubuntu3

[Launchpad Janitor (janitor)]

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

[Sami Jaktholm (sjakthol)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 893851, so it is being marked as such (the fix was never released in Quantal) Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.