On a Windows Vista-based or Windows Server 2008-based computer, you may have to wait five seconds for a USB video device to work if the USB selective suspend setting is enabled on the corresponding USB root hub

Consider the following scenario.

• You have a computer that is running Windows Vista or Windows Server 2008.
• You plug a USB video device into a USB root hub that has the USB selective suspend setting enabled.
• An application uses the USB device while the device is in selective suspend mode.

In this scenario, you may have to wait five seconds before the USB device starts to work. During this period, the application that uses the USB device appears unresponsive. For example, when you run an application to use a USB camera that is in selective suspend mode, you may have to wait five seconds for the video to appear in the application.

This problem typically occurs on computers that have multiple processors, multiple cores, or the hyper-threading feature.

This problem occurs because a deadlock condition may occur when a USB device resumes from selective suspend mode. This deadlock condition is ended by a five-second time-out.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing the problem described in this article. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

To apply this hotfix on a Windows Vista-based computer, you must have Windows Vista Service Pack 1 installed on the computer. For more information, click the following article number to view the article in the Microsoft Knowledge Base: No prerequisites are required for Windows Server 2008-based computers.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista and Windows Server 2008 file information notes

• The files that apply to a specific product, milestone (RTM, SPn), and service branch (LDR, GDR) can be identified by examining the file version numbers as shown in the following table.

  Version	Product	Milestone	Service branch
  6.0.6001.22xxx	Windows Vista SP1 and Windows Server 2008 SP1	SP1	LDR

• Service Pack 1 is integrated into Windows Server 2008. Therefore, RTM milestone files apply only to Windows Vista.
• The MANIFEST files (.manifest) and MUM files (.mum) installed for each environment are listed separately. MUM and MANIFEST files, and the associated security catalog (.cat) files, are critical to maintaining the state of the updated component. The security catalog files (attributes not listed) are signed with a Microsoft digital signature.

For all supported 32-bit versions of Windows Server 2008 and Windows Vista

For all supported 64-bit versions of Windows Server 2008 and Windows Vista

For all supported Itanium-based versions of Windows Server 2008

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

How to enable the USB selective suspend setting

To enable the USB selective suspend setting on a USB root hub, follow these steps:

1. Click Start, type power options in the Start Search box, and then press ENTER.
   
   If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
2. Click Change plan settings for the selected plan.
3. Click Change advanced power settings.
4. Expand USB settings, expand USB selective suspend setting, and then make sure that Enabled is selected.
5. Click OK.
6. Click Start, type device manager in the Start Search box, and then press ENTER.
7. Expand Universal Serial Bus controllers, right-click one of the USB Root Hub nodes, and then click Properties.
   
   Note Each USB Root Hub node corresponds to a USB root hub on your computer.
8. On the Power Management tab, make sure that the Allow the computer to turn off this device to save power check box is selected.
9. Click OK.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:

Additional file information for Windows Server 2008 and for Windows Vista

Additional files for all supported 32-bit versions of Windows Server 2008 and of Windows Vista

Additional files for all supported 64-bit versions of Windows Server 2008 and of Windows Vista

Additional files for all supported Itanium-based versions of Windows Server 2008