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The GETPOWERMANAGEMENT and SETPOWERMANAGEMENT display driver escape codes allow an application to put a display driver into various power management modes, independent of GDI calls that make use of the display driver's DrvPowerHandlerfunction. The most common use of these escape codes is in starting and stopping screen saver programs, wherein the display can be turned off while the operating system keeps running. This is different than the processing that happens during a suspend/resume cycle, when the operating system calls the display driver's DrvPowerHandlerfunction 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 exact meaning of each of these states depends on a display driver's particular implementation. OEMs should note that none of the sample display drivers for the CEPC and ODO platforms implement the power management driver escape codes.
Last updated on Tuesday, July 13, 2004