Article ID: 968132 - View products that this article applies to.
USB devices attached to the same hub are very slow or completely unresponsive.
While multiple devices that are attached to the same hub are going into selective suspend, one of the devices on the hub can receive a wake request. If this happens before the suspend request has completed, the devices become unstable.
Try these methods to work around this problem.
Method 1 Disable and enable the USB root hubUse Device Manager to disable and re-enable the USB root. This lets the controllers recover the USB port from its unresponsive condition.
To disable and re-enable the USB root, follow these steps:
Method 2 Restart the computerTry restarting the computer. After the computer has restarted, check whether the problem is resolved.
If restarting the computer resolved the problem, you are finished. If this method did not resolve the problem, go to Method 3.
Method 3 Disable Selective Suspend featureIf the first two methods did not work for you, you can disable the Selective Suspend feature. However, be aware that when the Selective Suspend feature is disabled, all USB host controller drivers (and therefore all USB ports and connected USB devices) in the system are affected. Therefore, your computer cannot suspend any USB devices that are connected to it, and the USB devices can continue to use power while connected to the computer. Additionally, the Allow the computer to turn off this device to save power check box does not appear on the Power Management tab for the USB root hub.
You can disable the USB Selective Suspend feature by editing the registry. The USB device may become unresponsive because of a race condition in the Selective Suspend feature. The Selective Suspend feature suspends the USB device to efficiently maintain battery power by enabling the computer to turn off the USB device. However, sometimes this feature may not correctly wake up the USB device. Therefore, the USB device is unresponsive when you try to use it.
You might want to disable this feature for server products where power management is not important or required.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756To disable the Selective Suspend feature, follow these steps:
(http://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
Microsoft has confirmed that this is a problem in the USB subsystem on Windows XP SP2 and SP3.
Article ID: 968132 - Last Review: March 11, 2009 - Revision: 1.0