Microsoft KB Archive/918005

= Battery power may drain more quickly than you expect on a portable computer that is running Windows XP or Windows Server 2003 =

Article ID: 918005

Article Last Modified on 10/15/2007

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APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Enterprise Edition
 * Microsoft Windows Server 2003, Standard x64 Edition
 * Microsoft Windows Server 2003, Enterprise Edition for Itanium-based Systems
 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional x64 Edition

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SYMPTOMS
When you unplug the AC power from a portable computer that is running Microsoft Windows XP Service Pack 2 (SP2) or Microsoft Windows Server 2003, the battery may drain more quickly than you expect. Therefore, the operating system may shut down prematurely.



CAUSE
This problem may occur if one of the following conditions is true:
 * The portable computer cannot enter the deeper Advanced Configuration and Power Interface (ACPI) processor idle sleep states.

This occurs when the USB 2.0 driver leaves the asynchronous scheduler component running continuously. This prevents the processor from entering the deeper ACPI processor idle sleep states (C-states). C-states save power when the processor is not busy. These states range from C0 to C3 or C4. Typically, an idle portable computer uses the C3 and C4 states to preserve battery power. If an idle portable computer cannot enter or maintain the C3 or C4 states, the battery power drains more quickly. This problem is fixed by installing the download that is available in this article.
 * The USB host controller is unable to turn off.

This typically occurs when devices are removed from a nested USB hub that is attached to the host controller. The host controller does not recognize the device removal. Therefore, the controller is never turned off. This prevents the processor from entering the ACPI processor idle sleep states. This problem is not fixed by installing the download that is available in this article.
 * The USB host controller uses the periodic scheduler for USB 2.0 devices.

This typically occurs when devices that rely on the periodic scheduler are attached to the host controller. These may be isochronous (Isoch) devices such as audio devices. Or, they may be interrupt devices such as mouse or keyboard. This problem is not fixed by installing the download that is available in this article.

Note Various factors can affect battery power other than the type of USB devices and their configuration. For example, various programs that run on portable computers may have different power consumption requirements. Additionally, the various types of batteries that are used can also affect battery power. Therefore, you may not notice any improvement in battery power after you apply this update.



Windows XP update information
The following file is available for download from the Microsoft download center:

Download the Windows XP (KB918005) package now.

Prerequisites
You must install Windows XP SP2 before you install the update.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

322389 How to obtain the latest Windows XP service pack

Restart requirement
After you apply this update, the update forces a restart of the computer.

File information
The English version of this update has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003 hotfix information
A supported hotfix is now available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
You must install Windows Server 2003 Service Pack 1 (SP1) or Windows Server 2003 SP2 before you install the hotfix.

Note The x64-based versions of Windows do not require that you install Windows Server 2003 SP1 before you install the hotfix.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

889100 How to obtain the latest service pack for Windows Server 2003

Restart requirement
After you apply this hotfix, the hotfix forces a restart of the computer.

Hotfix replacement information
This hotfix does not replace any other hotfixes.

File information
The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003, x86-based versions


STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
The x64-based versions of Windows Server 2003 and Windows XP Professional x64 Edition are based on the Windows Server 2003 code tree. Service and support activities for Windows XP Professional x64 Edition use the Windows Server 2003 code tree and do not use the Windows XP client tree.

For more information about the x64-based versions of Windows Server 2003 and Windows XP Professional x64 Edition, click the following article number to view the article in the Microsoft Knowledge Base:

888733 A description of the x64-based versions of Windows Server 2003 and of Windows XP Professional x64 Edition

For more information about the terms that are used to describe software updates, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbqfe kbpowerman atdownload kbexpertisebeginner kbhotfixserver KB918005

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