Best Practices for Power Manageable Device Drivers
Other versions of this page are also available for the following:
.gif "A hyphen indicates that the information in this topic is not relevant for this platform, or that the platform does not support the API that is listed.")
.gif "A checkmark indicates that the information in this topic is relevant for this platform, and that any API listed is also supported on this platform.")
8/28/2008
Microsoft recommends that a device driver expose all possible power management capabilities, and that it function properly regardless of whether a run-time image takes advantage of the power management capabilities of the Windows Embedded CE OS. These power-management best practices might affect the external interface of a device driver.
The following list shows best practices for power management:
- Expose the power management stream IOCTLs in client drivers.
- Do not expose the deprecated IOCTL_POWER_QUERY.
- Handle the XXX_PowerDown (Device Manager) and XXX_PowerUp (Device Manager) stream interface driver entry points correctly.
- Call the bus parent of a device driver for power management.
For example, after obtaining a handle to the bus with CreateBusAccessHandle, you can use functions such as GetDevicePowerState and SetDevicePowerState to request that the bus driver retrieve or set the device's power state. - Perform power management in a device driver when the run-time image does not take advantage of the power management that the OS provides.
- Handle interleaved power management stream IOCTLs and interleaved I/O operations.
See Also
Reference
CEDDK Dynamic-Link Library Bus Access Reference
Concepts
Bus Drivers
Windows Embedded CE Drivers