Computer won't automatically suspend

[csu333]

Or: "Why is DPMS off for my screens ?"

I just travelled a quite long journey to find out why my computer wouldn't go to sleep anymore. I first tried to follow the steps given here: https://wiki.ubuntu.com/DebuggingGNOMEPowerManager with little luck (as I have a standalone computer, I don't have much upower traffic) so I focused on gnome-settings-daemon (whose --no-daemon options just don't work).

After much research, I found out that the power plugin just didn't start. Looking in the code (gsd-power-manager, I try to find anwers where I can), I noticed that if the power-manager cannot clear dpms timeouts, the manger just didn't start.

So I issued a: xset q | grep -A1 DPMS
DPMS (Energy Star):
  Standby: 360 Suspend: 360 Off: 420
  DPMS is Disabled

and indeed my DPMS is disabled. Enabling it then restarting gnome-settings-daemon (killall then start with --no-debug) I see that the power plugin starts just fine and my computer goes to sleep as expected.

I checked xorg.conf that DPMS option was present and it is indeed.

So my question is: "Why is DPMS off for my screens ?"
I'm also wondering why the power plugin could start if DPMS is off ?

I must add power-wise information: my kernel starts with "noapic" option otherwise, my computer won't resume.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: gnome-settings-daemon 3.2.2-0ubuntu2.1
ProcVersionSignature: Ubuntu 3.0.0-15.25-generic 3.0.13
Uname: Linux 3.0.0-15-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Thu Jan 5 21:03:40 2012
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release amd64 (20100427.1)
SourcePackage: gnome-settings-daemon
UpgradeStatus: Upgraded to oneiric on 2011-11-16 (50 days ago)

[csu333 (csu333-ubuntu)]

I have to add some information to this bug:
 * There is apparently some race condition as my computer sometimes does go to sleep (even if DPMS is disabled)
 * DPMS disabled is probably more a question than a bug
 * The two bugs I see are:
    1 ) The power plugin not correctly starting when he cannot change DPMS mode:
(gnome-settings-daemon:4775): power-plugin-WARNING **: Unable to start power manager: Could not change DPMS mode
        I don't understand why a non functionning DPMS would preventmy computer from suspending. Only dimming would be affected but it is disabled anyway.
    2 ) Setting variable org.gnome.settings-daemon.plugins.power idle-dim-time (using dconf editor or gsettings) sets the idletime alarm bypassing previous check (well, at least, I have a workaround)

[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.