Display Driver Escape Codes
Applications may need to communicate directly with a display driver. An escape code mechanism makes this possible. Applications can invoke the ExtEscape function to pass an escape code and optional data to a display driver. ExtEscape, in turn, passes those parameters to the display driver's DrvEscape function. DrvEscape processes the escape code, returns a value to ExtEscape, which then returns the value to the application. DrvEscape should take no action and return zero for unsupported escape codes.
The following table shows the escape codes for display drivers. You can define additional driver-specific escape codes, starting at the decimal value 100,000. Microsoft reserves all escape code values up to 99,999. Not all sample display drivers implement these escape codes.
| Escape code | Value | Description |
|---|---|---|
| QUERYESCSUPPORT | 8 | Determines whether a display driver supports a particular escape code. |
| GETVFRAMEPHYSICAL | 6144 | Returns the physical memory location of the video frame buffer. |
| GETVFRAMELEN | 6145 | Returns the length of the video frame buffer. |
| DBGDRIVERSTAT | 6146 | Returns display driver statistics. |
| SETPOWERMANAGEMENT | 6147 | Requests a particular power management state. |
| GETPOWERMANAGEMENT | 6148 | Queries the current power management state. |
| CONTRASTCOMMAND | 6149 | Applies a display contrast setting. |
| DRVESC_GETGAMMAVALUE | 6202 | Retrieves the gamma value by calling GetGammaValue. GetGammaValue is part of Ctlblt.lib and should not be called by the application. Applications also should not use the ExtEscape function to invoke this driver. Set the gamma value through the SystemParametersInfo function with the SPI_GETFONTSMOOTHINGCONTRAST flag. |
| DRVESC_SETGAMMAVALUE | 6201 | Sets the gamma value by calling SetGammaValue. Applications should not use the ExtEscape function to invoke this driver. Set the gamma value through the SystemParametersInfo function with the SPI_SETFONTSMOOTHINGCONTRAST flag. |
| DRVESC_SETSCREENROTATION | 6301 | Sets the screen rotation value. |
| DRVESC_GETSCREENROTATION | 6302 | Retrieves the screen rotation value. |
| DRVESC_SAVEVIDEOMEM | 6501 | Saves the video RAM that must persist across a suspend or resume operation.
If HKEY_LOCAL_MACHINE\SYSTEM\GWE\PORepaint is 3, DRVESC_SAVEVIDEOMEM is invoked at suspend time. |
| DRVESC_RESTOREVIDEOMEM | 6502 | Restores the contents of the video RAM after resuming operation. |
| DRVESC_QUERYVIDEOMEMUSED | 6503 | Returns the amount of video memory in use. This is used to determine how much nonvolatile memory needs to be allocated before the save operation. |
| Reserved | 6150 through 99,999 | Reserved for future use. |
See Also
Node2D | Advanced Display Driver Power Management | Contrast Control | Display Driver Architecture | Display Driver Extensions | Display Driver Samples
Last updated on Tuesday, May 18, 2004
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