The "Wake on Ring" feature still wakes a Windows Vista-based computer even after you disable the "Allow this Device to wake the Computer" option

There are key differences between Windows XP and Windows Vista where power-management functionality is concerned. One of these differences concerns how the Windows Vista power-management feature works for the HD audio controller and for any child devices. For example, assume that you decide to disable an HD audio controller's Wake on Ring feature on a Windows Vista-based computer by disabling the Allow this Device to wake the Computer option. In this situation, the Wake on Ring feature still wakes the computer from sleep and from hibernation.

When the Wake on Ring feature is enabled, the computer continues to trickle power to the HD audio chip. This behavior also occurs on a Windows Vista-based computer even after you disable the HD audio chip.

To work around this issue, disable the HD audio controller and the Wake on Ring feature. When you do this, a small trickle of power is conserved when the system transitions into sleep or into hibernation.

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

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 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 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

No prerequisites are required.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace a previously released hotfix.

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, x86-based versions

Windows Vista, 64-bit versions

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

When the computer is connected to an AC power supply, and it enters sleep or hibernation, the HD audio chip continues to use some power. If the computer is transitioned to DC power while it is asleep or in hibernation, devices such as the HD audio controller continue to use power. This behavior may not be optimal for extended sleep or for hibernation if there is no AC power supply.

Additionally, even when you disable the Allow this device to wake the computer option for HD audio, this does not disable the system bus. Therefore, child devices continue to use power.