Double brightness events after logging in.

[Mark Smith]

output of lsb_release -rd
Description: Ubuntu oneiric (development branch)
Release: 11.10

Package:
gnome-settings-daemon:
  Installed: 3.1.90-0ubuntu1
  Candidate: 3.1.90-0ubuntu1
  Version table:
 *** 3.1.90-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ oneiric/main amd64 Packages
        100 /var/lib/dpkg/status

Expected result: At the login screen, brightness keys increase and decrease brightness by one step. After logging in, brightness keys continue to increase and decrease brightness by one step.

Actual result: At the login screen, brightness keys increase and decrease brightness by one step (same as expected, OK.) After logging in, brightness increases and decreases by two steps whenever a brightness key is pressed.

This specifically seems to apply to the POWER plugin for gnome-settings-daemon. setting "active" to false via
"gsettings set org.gnome.settings-daemon.plugins.power active false" returns the behavior to normal, but removes the gnome power indicator. However, since the battery indicator is present at the login screen, there must be a second application, hotkey, etc, trying to change brightness.
---
ApportVersion: 1.23-0ubuntu3
Architecture: amd64
DistroRelease: Ubuntu 11.10
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
NonfreeKernelModules: nvidia
Package: upower 0.9.13-1
PackageArchitecture: amd64
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 3.0.0-12.20-generic 3.0.4
Tags: oneiric running-unity
Uname: Linux 3.0.0-12-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm admin cdrom dialout lpadmin plugdev sambashare

[Walter Garcia-Fontes (walter-garcia)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This bug did not have a package associated with it, which is important for ensuring that it gets looked at by the proper developers. You can learn more about finding the right package at https://wiki.ubuntu.com/Bugs/FindRightPackage . I have classified this bug as a bug in Upower

Please also execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect 839281

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://help.ubuntu.com/community/ReportingBugs.

[Mark Smith (tntc-tig)]

I switched back to stable Ubuntu for a while, but I am now back on Oneric. First, I'd like to point out that but 527157 is likely closely related to this bug. https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/527157

I plan on running apport-collect 839281 just as soon as I get my oneric install finished.
For the record, KDE does not exhibit this bug. It is gnome specific. As far as I can tell, Gnome's power plugins try every possible way of increasing and decreasing the brightness, and in many cases this results in more than one brightness event being sent. While this is probably preferable to having NO brightness adjustments, it's certainly not ideal to have brightness levels reduced from 8 to 4.

[Mark Smith (tntc-tig)]

apport information

[Launchpad Janitor (janitor)]

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

[Mark Smith (tntc-tig)]

I think I have found a workaround, for those running across this.
I posted some info here, in this similar bug.
https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/527157

The practical upshot of all this is that adding the kernel parameter
acpi_backlight="vendor"
seems to give me proper brightness levels across the board. There were some side effects, namely my screen would go to sleep (due to the power manager timer) and not wake up. I'd suggest setting your screen to never go to sleep unless you close the lid. This "fixed" the comatose screen issue for me.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.3 kernel[1] (Not a kernel in the daily directory). Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag(Only that one tag, please leave the other tags). This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[1] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.3-rc7-precise/