VideoPortIsNoVesa function

Description

The VideoPortIsNoVesa function determines whether a video miniport driver that does not support Plug and Play (PnP) is restricted to legacy VGA resources.

Return value

If VideoPortIsNoVesa returns TRUE, then a non-PnP video miniport driver must restrict its hardware access to legacy VGA resources. Otherwise, the video miniport driver is permitted to use non-legacy VGA resources.

Remarks

This function is useful only to vga.sys, which is a system-supplied video miniport driver that does not support PnP. This function provides no pertinent information to video miniport drivers that support PnP and therefore is no use to IHVs.

If VideoPortIsNoVesa returns TRUE, then the video miniport driver must access the display adapter only through legacy VGA resources (I/O 3B0 through 3DF; memory A0000 through BFFFF). Specifically, if VideoPortIsNoVesa returns TRUE, the video miniport driver must not attempt to call the Int10 functions, which are implemented by the video port driver.

For more information about the Int10 functions, see Int10 Functions Implemented by the Video Port Driver.