The "wake on ring" feature still wakes a Windows Vista-based computer when you set an HD audio controller not to wake the computer

You set a high definition (HD) audio controller not to wake a Windows Vista-based computer by using the Allow this Device to wake the Computer option in Windows Vista. However, the "wake on ring" (WOR) feature still wakes the computer from sleep and from hibernation.

This problem occurs because the computer continues to trickle power to the HD audio chip if you disable the HD audio chip, and the WOR feature is enabled. You must disable the HD audio controller, and you must also disable the WOR feature. When you disable the HD audio controller and the WOR feature, a small trickle of power is conserved when transitioning into sleep mode or into hibernation.

To work around this problem, disable the WOR feature, and remove the AC power supply so that the computer runs on battery power. Then, the HD audio controller bus can no longer wake the computer.

You can selectively disable the WOR feature and the HD audio controller. To do this, follow these steps:

1. Click Start
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   , type Device Manager in the Start Search box, and then click Device Manager in the Programs list.
   
   
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   If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
2. In Device Manager, expand System Devices.
3. Right-click the HD audio device, and then click Properties.
4. Click the Power Management tab.
5. Click to clear the Allow this device to wake the computer check box, and then click OK.
6. Expand the Modem section in Device Manager, and then click Properties.
7. Click the Power Management tab.
8. Click to clear the Allow this device to wake the computer check box, and then click OK.
9. Exit Device Manager.

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

When the computer is plugged into AC power and enters sleep mode, the HD audio chip continues to use power. Then, if a computer is transitioned to battery power while Windows is in hibernation, the devices continue to draw current. This may not be desirable for extended sleep durations if no AC power is supplied.

Microsoft is researching this problem and will post more information in this article when the information becomes available.