Microsoft KB Archive/899860

= A USB 1.1 video device may not work correctly if you plug the USB 1.1 video device into a USB 2.0 hub on a Windows XP-based computer =

Article ID: 899860

Article Last Modified on 6/28/2005

-

APPLIES TO


 * Microsoft Windows XP Home Edition
 * Microsoft Windows XP Professional
 * Microsoft Windows XP Tablet PC Edition
 * Microsoft Windows XP Media Center Edition 2002

-





SYMPTOMS
If you plug a universal serial bus (USB) version 1.1 video device into a USB version 2.0 hub, the USB video device may not function correctly. The video image may be garbled, or the video image may not be displayed at all.



CAUSE
This problem occurs because the Windows XP host controller driver for Enhanced Host Controller Interface (EHCI) USB controllers does not enforce this ordering requirement. The USB 2.0 specification requires that the complete-splits for different isochronous transfers be in the same order as their respective start-splits. The host controller driver is responsible for enforcing this ordering rule. Because the Windows XP host controller driver for EHCI USB controllers does not enforce this ordering requirement, the USB 2.0 hub may fail the complete-split transfer requests from the host.



WORKAROUND
To work around this issue, bypass the USB hub and plug the camera directly into a USB 2.0 port on the Windows XP-based computer.



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

Keywords: kbtshoot kbprb KB899860

-

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

© Microsoft Corporation. All rights reserved.