## Display Device Driver Reference for OS/2

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### Monitor Timings Support

The PMI defines eight display-timing-related variables as mode keyvariables . These variables facilitate selection of the mode, depending on the current monitor specification and sizing of the active display for the current mode. The MonitorModeInfo section contains all of the timing- related PMI key variables.

The display-timing-related variables are:

VerticalRefresh Vertical refresh in Hz (rounded to the nearest integer)

HorizontalRefresh Horizontal refresh in KHz (rounded to the nearest integer )

HPolarityPositive Contains the Horizontal polarity (0,1) for the current mode selection

VPolarityPositive Contains the Vertical polarity (0,1) for the current mode selection

ScreenLeftEdge Represents the end of the horizontal blanking (HBP) in pixel count along the horizontal sweep (HSP)

ScreenRightEdge Represents the start of the horizontal blanking (HFP) in pixel count along the horizontal sweep (HSP)

ScreenTopEdge Represents the end of the vertical blanking (VBP) in line count along the vertical sweep (VSP)

ScreenBottomEdge Represents the start of the vertical blanking (VFP)

The last four timing elements, defining the start and end of the horizontal active display and start and end of the vertical active display, are suggested as mode elements in order to enhance visual quality. Their values are never directly communicated to the end user configuring the adapter, only the net results. The values are manipulated through a TuneDisplay function as part of the SetMode or upon the end user's configuration request. See [TuneDisplay] section in PMI Sections.

There is no interface for specification and manipulation of the widths of the Horizontal Sweep (HSP) and Vertical Sweep (VSP) signals.

If an adapter is capable of supporting both non-CRT- and CRT-style displays , modes of both types should be listed. Non-CRT Mode sections are those that have 0 for both horizontal and vertical refresh rate.

If the adapter has monitor sensing, identification, and auto-adjusting capability built in so that software manipulation of the timing-related registers is not required, none of the timing-related mode elements have to be specified. No MonitorModeInfo sections should be included and monitor sizing parameters and the TuneDisplay function should not be listed.

The vendor providing the .PMI file can supply either a single MonitorModeInfo, which denotes the upper limit for horizontal and vertical refresh, or a number of MonitorModeInfo sections with distinct sets of horizontal and vertical refresh values. In the first case, the OS/2 Warp configuration utility offers refresh values that are part of the current monitor definition for the desired resolution, as long as the monitor specification is within the range specified by the adapter. If more than one MonitorModeInfo section exists per mode, all of those within the monitor's specification are offered as a selection to the user by the OS/2 Warp Video Configuration Manager. Polarity PMI keyvariables are not required, unless an exact match with the monitor's capabilities is desired by the adapter vendor.

For a full description of Video Configuration, see