## Display Device Driver Reference for OS/2

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### SVGADATA PMI file

The VIDEOPMI interface is driven by the sections of the There are two main types of sections:

Query sections that describe adapter capabilities

Set sections that service hardware programming requests

Query sections provide information on hardware description, list of ports, list of supported modes, and the range or set of supported timing values. The Set sections provide the capability to identify adapters; unlock registers; cleanup, size, and position the active display; set a mode; save and restore a mode, and the VRAM used by the mode.

The VIDEOPMI language defines a video adapter as a hardware controller in terms of its I/O and memory addresses that are programmable by the CPU. The video controller can be a dumb frame VGA/SVGA, an accelerator, or a general-purpose coprocessor. The must contain all of the informational sections and a minimal set of Set sections (see PMI Sections). An adapter description starts with its Hardware section, followed by IdentifyAdapter, a number of support sections, and a list of all available modes with the corresponding SetMode sections. PMI language or as a call to an externally defined function. The two implementations are discussed in detail under Code vs. PMI in this chapter.

The PMI facilitates dynamic hardware configuration, which includes port remapping as well as adding or removing an adapter and its PMI definition. It also includes changing the attached display and multiple instances of the same video hardware driven by the same The interface defines monitor timing variables needed to drive a CRT monitor. These variables provide extensive monitor support and a consistent user configuration interface. The PMI language also facilitates programming of the support chips that can be mapped into the I/O and memory space addressable by the CPU, such as external clock-synchronizing chips or smart Digital-to-Analog Converters ( DACs).

files are to be provided by the video chip or adapter manufacturers or by the providers of the display drivers. The file should be part of the video adapter installation kit, either as a pre-manufactured flat file or one created by the OEM's installation utility.