## Presentation Device Driver Reference for OS/2

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### Graphics Engine/Presentation Driver Design Changes

In the graphics engine for OS/2 Warp, Version 3, the presentation driver has to support only the current OS2_PM_DRV_ENABLE and DEVESC_ functions. A new enable subfunction call, OS2_PM_DRV_ENABLE: Subfunction 0Eh - QueryDeviceSurface, has been added so that the graphics engine can manage the formerly mandatory functions for presentation drivers.

This graphics engine is designed so that a developer can create a presentation driver with minimal effort, and then incrementally add function that supports specific hardware. In order to achieve this, the new graphics engine does the following:

Manages Presentation Manager contextual and state information

Performs rasterization into a linear address specified by the presentation driver

Provides a set of device support routines