FIX: The message-signaled interrupts (MSIs) feature is not enabled on VIA processors on a computer that is running Windows 7 or Windows Server 2008 R2

Consider the following scenario:

• You have a computer that is running Windows 7 or Windows Server 2008 R2.
• The computer has one or more VIA Technologies, Inc (VIA) processors.
• By default, the message-signaled interrupts (MSIs) feature is not enabled on these VIA processors even if they support MSIs.

In this scenario, some devices or applications that rely on the MSIs feature do not work as expected.

For example:

• The Hyper-V feature does not work.
• Some PCI-Express VGA cards do not work correctly.

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

There are no prerequisites for installing this hotfix.

Restart information

You must restart the computer after you apply this hotfix.

File information

The global 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.

For all supported x86-based versions of Windows 7

For all supported x64-based versions of Windows 7 and Windows Server 2008 R2

Additional notes

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.

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

For more information about Message-Signaled Interrupts, visit the following Microsoft Developer Network (MSDN) Web site: