Chapter 7 Video Miniport Drivers

Windows NT® video miniport drivers are adapter-specific, kernel-mode drivers. Each miniport driver links itself with the system-supplied video port driver, which is a kernel-mode dynamic-link library. A video miniport driver calls only the port driver’s VideoPortXxx functions to communicate with the system and with its hardware.

NT video miniports include the following system-supplied header files:

• miniport.h with the basic types, constants, and structures for both SCSI and video miniport drivers

• video.h with the video-specific structures, such as the VIDEO_REQUEST_PACKET, miniport function prototypes, and VideoPortXxx declarations

• ntddvdeo.h with the system-defined I/O control codes and corresponding structures that are sent in VRPs (video request packets) to video miniport drivers

• devioctl.h with the macros and constants used to define I/O control codes

• dderror.h with the Win32® status constants that miniport drivers return to the video port driver, which are also returned to the miniport’s corresponding kernel-mode display driver.

In this document, all miniport HwXxx routines are referred to as HwVidXxx routines for the purpose of clarity. In the header files and programmatically, these routines will not have the Vid prefix. The routines, whose addresses will be stored in a dispatch table, can have any name. For the purposes of this document, these routines will have names beginning with HwVidXxx.

For more detailed information about the system-defined I/O control codes, constants, structures, and function prototypes in these header files, see the Graphics Driver Reference.