"Code 28" Error Message About ACPI-Compliant Embedded Controller Appears on IBM ThinkPad (286717)


The information in this article applies to:

  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
This article was previously published under Q286717

SYMPTOMS

After you install Windows XP on an IBM ThinkPad portable computer (model A20M, A21M, or X20), Device Manager displays the following error message, which is marked with a yellow icon:
UNKNOWN DEVICE
Code 28 -- No drivers are installed for this device. The location of the device is listed on LOCATION: on Microsoft ACPI-Compliant Embedded Controller.

CAUSE

This behavior occurs because Windows XP has no built-in Advanced Configuration and Power Interface (ACPI) driver for the embedded ACPI controller that comes with these models of the IBM ThinkPad portable computer.

RESOLUTION

To resolve this behavior, contact IBM to obtain an updated driver for the embedded ACPI controller.

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

The third-party products that are discussed in this article are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.

For information about how to contact IBM, click the appropriate article number in the following list to view the article in the Microsoft Knowledge Base:

65416 Hardware and Software Third-Party Vendor Contact List, A-K

60781 Hardware and Software Third-Party Vendor Contact List, L-P

60782 Hardware and Software Third-Party Vendor Contact List, Q-Z

For more information about ACPI, review the following Microsoft Knowledge Base articles:

244806 Overview of Power Management in Windows 2000

242495 Troubleshooting Advanced Power Management in Windows 2000

Modification Type:MajorLast Reviewed:10/18/2001
Keywords:kb3rdparty kbenv kberrmsg kbHardware kbprb KB286717
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