I'm not sure if this is a Unity bug (so please don't shoot me if I'm wrong)...
I have a Lenovo T430s with the optional, secondary, Bay Battery installed. At times, the battery indicator will only display the status of one battery. Opening "Power Statistics" also displays only one battery. Unity is confused and thinks there is only one battery, and that it is actually charging when in fact the machine is discharging from the secondary battery. I guess this will cause the machine to ignore any power savings options until the bay battery runs out of juice and the main battery starts to drain.
> dmesg |grep batt
[ 1.052681] ACPI: Deprecated procfs I/F for battery is loaded, please retry with CONFIG_ACPI_PROCFS_POWER cleared
[ 1.052694] ACPI: Battery Slot [BAT0] (battery present)
[ 1.052710] ACPI: Deprecated procfs I/F for battery is loaded, please retry with CONFIG_ACPI_PROCFS_POWER cleared
[ 1.052728] ACPI: Battery Slot [BAT1] (battery present)
[ 1.063049] ACPI Exception: AE_ALREADY_EXISTS, Evaluating _BIF (20110623/battery-419)
[ 1.063055] ACPI: Battery Slot [BAT1] (battery present)
[ 1.064222] ACPI: Battery Slot [BAT0] (battery present)
Steps to reproduce:
Install bay battery
Reboot
Workaround:
Connect and disconnect charger (if you happen to be near a power outlet).
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: unity 5.14.0-0ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24
Uname: Linux 3.2.0-29-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.1
Architecture: amd64
CompizPlugins: [core,composite,opengl,compiztoolbox,decor,vpswitch,snap,mousepoll,resize,place,move,wall,grid,regex,imgpng,session,gnomecompat,animation,fade,unitymtgrabhandles,workarounds,scale,expo,ezoom,unityshell]
Date: Sun Feb 3 08:43:05 2013
InstallationMedia: Ubuntu 12.04.1 LTS "Precise Pangolin" - Release amd64 (20120823.1)
MarkForUpload: True
ProcEnviron:
LANGUAGE=en_CA:en
TERM=xterm-256color
PATH=(custom, no user)
LANG=en_CA.UTF-8
SHELL=/bin/bash
SourcePackage: unity
UpgradeStatus: No upgrade log present (probably fresh install)
Status changed to 'Confirmed' because the bug affects multiple users.