Microsoft KB Archive/894956

= An IEEE 1394 device drive may stop working when you turn on another IEEE device in Windows XP =

Article ID: 894956

Article Last Modified on 2/28/2005

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APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional

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SYMPTOMS
When you turn on the power for an Institute of Electrical and Electronics Engineers, Inc. (IEEE) 1394 device that is connected to your Microsoft Windows XP-based computer, another IEEE 1394 device may stop working.



CAUSE
This problem may occur if the following conditions are true:
 * You have devices that use the IEEE 1394-1995 standard and devices that use the newer IEEE 1394-2000 standard connected to your computer.
 * These devices are chained together on the same IEEE 1394 bus or hub.

When you turn on the power for a device that uses the IEEE 1394-2000 standard, Windows XP optimizes the gap count for all devices that are chained together on the IEEE 1394 bus. This triggers a reset of the IEEE 1394 bus. Some IEEE 1394-1995-based devices may not be correctly re-enumerated when this problem occurs.



WORKAROUND
To work around this problem, use one of the following methods.

Note Do not use these methods while file transfers to IEEE 1394 devices are in progress. Disk corruption or data loss may occur in this scenario. Additionally, when you use these methods, IEEE 1394 devices that are chained together through the same IEEE 1394 bus may be disconnected.
 * Disable and then re-enable the 1394 host controller in Device Manager. To do this, follow these steps:
 * Click Start, click Run, type devmgmt.msc in the Open box, and then click OK.
 * In the device tree, expand IEEE 1394 Bus host controllers.
 * Right-click the IEEE 1394 Bus host controller, and then click Disable. Click Yes if you are prompted for verification.
 * Right-click the IEEE 1394 Bus host controller again, and then click Enable.
 * Close Device Manager.
 * Turn off the power for the IEEE 1394 device that is not working, and then turn the power back on again. Or, disconnect the IEEE 1394 device that is not working, and then connect the device again.



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

Additional query words: Firewire i.Link 1394a-2000

Keywords: kbtshoot KB894956

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