Increase System Power Efficiency with Idle Detection

Updated: April 23, 2008

File name: S0idle_driver.docx
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One way to improve a computer's power efficiency is to power down devices that aren't currently being used, even though the system may still be active and in its normal operating power state (S0). The practice of powering down an idle device while the system remains running is referred to as "runtime idle detection" or "S0 idle." A USB function driver supports runtime idle detection by implementing USB selective suspend. This white paper provides advice for driver developers on how to modify their function drivers to support runtime idle detection.

This information applies for the following operating systems:
Windows Server 2008
Windows Vista
Windows Server 2003
Windows XP
Windows 2000

What's New:

• Added more information about idle timers to this paper.

• Moved all information about USB selective suspend to "Selective Suspend in USB Drivers."

Included in this white paper:

• A Generic Algorithm for Supporting Runtime Idle Detection

• An Algorithm for Supporting Runtime Idle Detection on USB Devices

• Evaluating Driver Support for Runtime Idle Detection

• Determining the Runtime Idle Detection Policy

• Guidelines for Implementing Runtime Idle Detection

See Also

• Selective Suspend in USB Drivers