Microsoft KB Archive/283649

= &quot;ACPI BIOS is attempting to write to an illegal IO port address&quot; error message when you open the event viewer =

Article ID: 283649

Article Last Modified on 9/22/2006

-

APPLIES TO


 * Microsoft Windows XP Professional
 * Microsoft Windows XP Home Edition

-



This article was previously published under Q283649



SYMPTOMS
The following error message may be in the system event log when you open the event viewer:

Source: ACPI Category: None Type: Error Event ID: 5 User: N/A Computer: Machine_Name Description: AMLI: ACPI BIOS is attempting to write to an illegal IO port address (0x ), which lies in the 0xXXXX - 0xYYYY protected address range. This could lead to system instability. Please contact your system vendor for technical assistance.

For more information, see Help and Support Center at:

http://http://support.microsoft.com

Where  is one of the following:   Address or Range   Description 0x000 – 0x009     ISA DMA 0x020 – 0x021     PIC 0x040 – 0x043     Timer1, Refresh, Speaker, Control Word 0x048 – 0x04B     Timer2, Failsafe 0x070 – 0x071     CMOS/NMI enable 0x074 – 0x076     Extended CMOS 0x081 – 0x083     DMA 0x087             DMA 0x089             DMA 0x08A – 0x08B     DMA 0x08F             DMA 0x090 – 0x091     Arbitration Control Port, Card Select Feedback 0x093 – 0x094     Reserved, System board setup 0x096 – 0x097     POS channel select 0x0A0 – 0x0A1     Cascaded PIC 0x0C0 – 0x0DF     ISA DMA 0x4D0 – 0x4D1     Edge, level control registers for PIC 0xCF8 – 0xCFF     PCI Configuration Space Access Pair



CAUSE
This behavior may occur if your computer's basic input/output system (BIOS) tries to write to one of the earlier ports by using an AML [Advanced Configuration and Power Interface (ACPI) Machine Language] System IO operation region. Your try may be blocked by Microsoft Windows XP because accessing these ports by using this mechanism is considered dangerous and can cause system instability. This feature is designed to improve the stability of your computer's operating system.



STATUS
This behavior is by design.



MORE INFORMATION
Contact the BIOS vendor for a possible BIOS update. For more information, visit the following Microsoft Web site:

http://www.microsoft.com/whdc/system/pnppwr/powermgmt/BIOSAML.mspx

Additional query words: 0x80 0x400 0xcf8 0xcfc

Keywords: kburl kbeventlog kbevent kberrmsg kbhardware kbprb KB283649

-

[mailto:TECHNET@MICROSOFT.COM Send feedback to Microsoft]

© Microsoft Corporation. All rights reserved.