Microsoft KB Archive/935782

= A USB device takes a long time to resume from &quot;selective suspend&quot; mode on a Windows Vista-based computer that uses UHCI USB controllers =

Article ID: 935782

Article Last Modified on 8/29/2007

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APPLIES TO


 * Windows Vista Ultimate
 * Windows Vista Home Premium
 * Windows Vista Home Basic
 * Windows Vista Enterprise
 * Windows Vista Business
 * Windows Vista Business 64-bit Edition
 * Windows Vista Ultimate 64-bit Edition
 * Windows Vista Home Premium 64-bit Edition
 * Windows Vista Home Basic 64-bit Edition
 * Windows Vista Enterprise 64-bit Edition

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SYMPTOMS
On a Windows Vista-based computer that uses Universal Host Controller Interface (UHCI) USB controllers, a USB device takes a long time to resume from &quot;selective suspend&quot; mode. Usually, the USB device takes 500 to 1,200 milliseconds (ms) to resume from this mode.

Therefore, USB devices that are attached to the UHCI USB controller may take a long time to respond. For example, assume that you are using a fingerprint reader to capture user fingerprints. The fingerprint reader is attached to the UHCI USB controller on a Windows Vista-based computer. If the fingerprint reader is in &quot;selective suspend&quot; mode, the system may not capture the fingerprint after you swipe a finger on the receiver of the fingerprint reader. This behavior occurs because the fingerprint reader takes a long time to resume from &quot;selective suspend&quot; mode. You must swipe your finger again for the fingerprint reader to capture the fingerprint.

Note Typically, it takes about 20 ms to resume from &quot;selective suspend&quot; mode when you use either of the following configurations:
 * Microsoft Windows XP-based computers that use UHCI USB controllers
 * Windows Vista-based computers that use Open Host Controller Interface (OCHI) USB controllers



CAUSE
This problem occurs because Windows Vista has introduced a design change for the USB driver.

Windows Vista lets individual ports switch to &quot;selective suspend&quot; mode. However, the resume notification of a USB device that uses an UHCI controller does not trigger an interrupt unless the host controller is in &quot;global suspend&quot; mode. The resume notification is detected only when the rollover transfer descriptor (TD) is completed. The rollover TD is completed every 1,024 ms. Therefore, the USB device usually experiences a delay of 700 to 800 ms.



Hotfix information
A supported hotfix is now 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 this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next service pack that contains this hotfix.

To resolve this problem, submit a request to Microsoft Online Customer Services to obtain the hotfix. To submit an online request to obtain the hotfix, visit the following Microsoft Web site:

http://go.microsoft.com/?linkid=6294451

Note If additional issues occur or 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. To create a separate service request, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Prerequisites
No prerequisites are required.

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, 64-bit versions


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



MORE INFORMATION
To determine th type of USB controller that the computer is using, follow these steps:
 * 1) Click Start, type devmgmt.msc in the Start Search box, and then press ENTER.
 * 2) Expand Universal Serial Bus controllers, and then determine the type of USB controller that the computer is using.

For more information about &quot;selective suspend&quot; mode, visit the following Microsoft Web site:

http://msdn2.microsoft.com/en-us/library/ms793200.aspx

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

824684 Description of the standard terminology that is used to describe Microsoft software updates

Keywords: kbbug kbfix kbqfe kbpubtypekc kbexpertiseinter kbhotfixserver kbwinvistapostrtmfix KB935782

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