Screen dims unexpectedly then stays dim until adjusted

[Dave L]

Expected behaviour:
1) When "AC" power connected, screen does not dim.
2) "When System Settings->Brightness and Lock->Dim screen to save power" is unchecked, screen does not dim
3) When (1) and (2) are false, screen dims after a period of inactivity
4) When keyboard or mouse activity, screen will undim.

Behaviour after upgrade to 13.10
1) Screen dims randomly when AC power is connected, seemly after inactivity
2) Screen dims instantly if AC power is disconnected then reconnected
3) Screen does not undim on mouse movement or keypresses
4) Opening or clicking on the brightness and lock menu undims the screen.
5) "Dim screen to save power" setting makes no difference (other than that to adjust the setting, you cause condition 4)

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: linux-image-3.11.0-14-generic 3.11.0-14.21
ProcVersionSignature: Ubuntu 3.11.0-14.21-generic 3.11.7
Uname: Linux 3.11.0-14-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: dave 3034 F.... pulseaudio
                      dave 17396 F.... pulseaudio
Date: Thu Dec 26 22:51:21 2013
InstallationDate: Installed on 2013-06-24 (185 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Release amd64 (20130424)
MachineType: Hewlett-Packard HP Compaq 6530b (VC178ET#ABU)
MarkForUpload: True
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.11.0-14-generic root=/dev/mapper/main-root ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.11.0-14-generic N/A
 linux-backports-modules-3.11.0-14-generic N/A
 linux-firmware 1.116
SourcePackage: linux
UpgradeStatus: Upgraded to saucy on 2013-12-25 (1 days ago)
dmi.bios.date: 12/07/2011
dmi.bios.vendor: Hewlett-Packard
dmi.bios.version: 68PDD Ver. F.20
dmi.board.name: 30DD
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 96.23
dmi.chassis.asset.tag: CNU9492DHT
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.modalias: dmi:bvnHewlett-Packard:bvr68PDDVer.F.20:bd12/07/2011:svnHewlett-Packard:pnHPCompaq6530b(VC178ET#ABU):pvrF.20:rvnHewlett-Packard:rn30DD:rvrKBCVersion96.23:cvnHewlett-Packard:ct10:cvr:
dmi.product.name: HP Compaq 6530b (VC178ET#ABU)
dmi.product.version: F.20
dmi.sys.vendor: Hewlett-Packard

[Brad Figg (brad-figg)]

This change was made by a bot.

[penalvch (penalvch)]

Dave L, this would be an issue of gnome-power-manager, or whatever is used in Unity, does not inhibit systemd from handling buttons and lid events -> gnome-power-manager (Ubuntu). Please reassign if incorrect package/workflow.

For the Xubuntu variant (and potential WORAKROUND) of this please see https://bugs.launchpad.net/ubuntu/+source/xfce4-power-manager/+bug/1222021 .