Microsoft KB Archive/306580

= System May Become Unresponsive When Using a Modem =

Article ID: 306580

Article Last Modified on 5/18/2007

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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This article was previously published under Q306580



IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry



SYMPTOMS
When you are using a notebook computer that employs the Intel 440MX chipset and an AC'97 soft modem, you may experience the following symptom with Windows XP:
 * When you use the internal modem on the notebook computer, Windows XP may seem to stop responding (hang).

This problem has been confirmed to occur only on computers using the Intel 440MX chipset and an AC'97 soft modem. These computers require an updated system BIOS and an updated driver file (P3.sys) so that Windows XP can fully support the Intel SpeedStep Technology power-saving functionality concurrent with modem operations. As of November 2001, this configuration is typically found on only a small range of sub-compact laptop computers using the Intel 440MX chipset in support of the Mobile Intel Pentium III processor-M CPU.



RESOLUTION
To resolve this problem, obtain the latest service pack for Windows XP. For additional 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

There are three steps needed to correct this issue:
 * 1) Obtain an updated BIOS from your notebook computer manufacturer. For information about how to update the BIOS, please contact your notebook computer manufacturer.
 * 2) Apply the update below.
 * 3) Update the registry per the &quot;Enabling the New Driver to Use SpeedStep Technology&quot; instructions below.

This update is available on the Microsoft Windows Update Web site.

Download the &quot;Intel Pentium III Processor Update&quot; now

The English version of this fix should have the following file attributes or later:   Date         Time   Version      Size    File name --  29-Aug-2001  15:57  5.1.2600.10  37,248  P3.sys 29-Aug-2001 16:20                1,521  P3qfe.inf

Enabling the New Driver to Use SpeedStep Technology
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

After you install the fix from the Microsoft Windows Update Web site, you must make the following registry change:  Start Registry Editor (Regedit.exe). Locate and click the following key in the registry:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\P3\Parameters

You may have to create the Parameters key if it is not already present.

 On the Edit menu, click Add Value, and then add the following registry value:

Value name: HackFlags

Data type: REG_DWORD

Radix: Hexadecimal

Value data: 1

 Quit Registry Editor.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows XP Service Pack 1.

Additional query words: Intel 440 MX Errata #34

Keywords: kbhotfixserver kbqfe kbbug kbfix kbsetup kbwinxpsp1fix KB306580

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