Advanced Display Driver Power Management
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
The GETPOWERMANAGEMENT and SETPOWERMANAGEMENT display driver escape codes allow an application to put a display driver into various power management modes, independent of Graphic Display Interface calls that use the display driver's DrvPowerHandler function.
The most common use for these escape codes is in starting and stopping screen saver programs, when the display is turned off while the OS continues running. This is different than the processing that occurs during a suspend and resume cycle, when the OS calls the display driver's DrvPowerHandler function to shut down the display.
Applications must also pass a VIDEO_POWER_MANAGEMENT structure to ExtEscape when they use these escape codes.
The available power states, defined in the VIDEO_POWER_STATE enumeration, are VideoPowerOn, VideoPowerStandBy, VideoPowerSuspend, and VideoPowerOff. The meaning of these states depends on a display driver's implementation.
If you pass the VIDEO_POWER_STATE enumeration VideoPowerOff to ExtEscape, the driver puts the device into a different power state (POWER_STATE_IDLE), instead of just turning off the monitor. This functionality is different from previous versions of the display driver power management functions.
The MQ200 driver in %_WINCEROOT%\Public\Common\OAK\Drivers\Display\MQ200 supports these escape codes.
It is recommended that the backlight driver not forward softkey presses to the OS when the backlight is off.
To enable a backlight, you must make changes to the OS design, registry, and display driver. For more information, see Enabling a Backlight.
See Also
Concepts
Display Driver Escape Codes
Contrast Control
Display Driver Development Concepts
Display Driver Extensions
Display Driver Samples