acpi not communicating with battery on startup

[NoahY]

Binary package hint: acpi

On startup with my Acer Aspire 6930, there is no battery icon in my system tray, nor any warning if the battery is discharging or almost empty. It doesn't matter whether the laptop is plugged in or not, but if it is unplugged and I don't realize it, it will discharge until empty and shut off without offering any indication. Interestingly, when I enter the command:

cp -r /proc/acpi /tmp

Suddenly the battery icon is back. I think this also happens if, having been plugged in on startup, I unplug the laptop. It seems there is some problem with ACPI? Here is some relevant messages in dmesg | grep ACPI:

 [ 3.210050] ACPI Error (dswload-0790): [_T_0] Namespace lookup failure, AE_ALREADY_EXISTS
[ 3.210057] ACPI Exception: AE_ALREADY_EXISTS, During name lookup/catalog 20090521 psloop-227
[ 3.210063] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node ffff88013ba310e0), AE_ALREADY_EXISTS
[ 3.210073] ACPI: Marking method UBIF as Serialized because of AE_ALREADY_EXISTS error
[ 3.210105] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._Q09] (Node ffff88013ba3a0c0), AE_ALREADY_EXISTS
[ 3.210114] ACPI: Marking method _Q09 as Serialized because of AE_ALREADY_EXISTS error
[ 3.780185] ACPI Warning: \_SB_.PCI0.SAT0.PRT0._GTF: Return type mismatch - found Integer, expected Buffer 20090521 nspredef-940
[ 3.780239] ACPI Warning: \_SB_.PCI0.SAT0.PRT4._GTF: Return type mismatch - found Integer, expected Buffer 20090521 nspredef-940
[ 4.630437] ACPI Error (psargs-0359): [_T_0] Namespace lookup failure, AE_NOT_FOUND
[ 4.630442] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node ffff88013ba310e0), AE_NOT_FOUND
[ 4.630466] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1._BIF] (Node ffff88013ba310a0), AE_NOT_FOUND
[ 4.630492] ACPI Exception: AE_NOT_FOUND, Evaluating _BIF 20090521 battery-355
[ 4.630499] ACPI: Battery Slot [BAT1] (battery present)

ProblemType: Bug
Architecture: amd64
Date: Sat Feb 13 14:06:54 2010
DistroRelease: Ubuntu 9.10
NonfreeKernelModules: nvidia
Package: acpi (not installed)
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-19.56-generic
SourcePackage: acpi
Uname: Linux 2.6.31-19-generic x86_64

[Marco (0m3g4)]

[ 0.472667] ACPI: Battery Slot [BAT1] (battery absent)
[ 1.560301] ACPI Warning for \_SB_.PCI0.SAT0.PRT0._GTF: Return type mismatch - found Integer, expected Buffer (20090903/nspredef-1006)
[ 2.200342] ACPI Error (dswload-0781): [_T_0] Namespace lookup failure, AE_ALREADY_EXISTS
[ 2.200350] ACPI Exception: AE_ALREADY_EXISTS, During name lookup/catalog (20090903/psloop-230)
[ 2.200356] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node ffff88013ba2e100), AE_ALREADY_EXISTS
[ 2.200369] ACPI: Marking method UBIF as Serialized because of AE_ALREADY_EXISTS error
[ 2.200396] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1._BIF] (Node ffff88013ba2e0c0), AE_ALREADY_EXISTS
[ 2.200401] ACPI: Marking method _BIF as Serialized because of AE_ALREADY_EXISTS error
[ 2.200423] ACPI Exception: AE_ALREADY_EXISTS, Evaluating _BIF (20090903/battery-363)
[ 2.204307] ACPI Error (psargs-0359): [_T_0] Namespace lookup failure, AE_NOT_FOUND
[ 2.204314] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.BAT1.UBIF] (Node ffff88013ba2e100), AE_NOT_FOUND
[ 2.204352] ACPI Error (psparse-0537): Method parse/execution failed [\_SB_.PCI0.LPCB.EC0_._Q09] (Node ffff88013ba410e0), AE_NOT_FOUND