VideoPortMapBankedMemory function (video.h)

Article
05/26/2021

The VideoPortMapBankedMemory function is obsolete, and is supported only for Windows NT 4.0 and previous drivers. Windows 2000 and later drivers must use VideoPortMapMemory.

VideoPortMapBankedMemory remaps a bus-relative physical range of video memory into the corresponding display driver's virtual address space in response to a VRP with the IoControlCode member set to IOCTL_VIDEO_SHARE_VIDEO_MEMORY or IOCTL_VIDEO_MAP_VIDEO_MEMORY.

Syntax

VIDEOPORT_DEPRECATED VIDEOPORT_API VP_STATUS VideoPortMapBankedMemory(
  PVOID                   HwDeviceExtension,
  PHYSICAL_ADDRESS        PhysicalAddress,
  PULONG                  Length,
  PULONG                  InIoSpace,
  PVOID                   *VirtualAddress,
  ULONG                   BankLength,
  UCHAR                   ReadWriteBank,
  PBANKED_SECTION_ROUTINE BankRoutine,
  PVOID                   Context
);

Parameters

HwDeviceExtension

Pointer to the miniport driver's device extension.

PhysicalAddress

Specifies the bus-relative base address of the range to be mapped.

Length

Pointer to a variable specifying the total number of bytes of device memory to be mapped (regardless of bank size). VideoPortMapBankedMemory returns the actual size of the memory mapped, which can be rounded to a system-determined alignment boundary, in this parameter. However, the miniport and display drivers cannot access memory outside the range delimited by the input value at Length.

InIoSpace

Indicates the location of the range. This parameter can be one of the following values:

Value	Meaning
VIDEO_MEMORY_SPACE_DENSE	Obsolete
VIDEO_MEMORY_SPACE_IO	The range is in system I/O space rather than in memory space.
VIDEO_MEMORY_SPACE_MEMORY	The range is in memory space rather than in system I/O space.
VIDEO_MEMORY_SPACE_P6CACHE	The processor aggregates a sequence of write operations and sends them to a given cache line. The processor then flushes the cache. This flag is meaningful only when VIDEO_MEMORY_SPACE_IO is not set.
VIDEO_MEMORY_SPACE_USER_MODE	Indicates that the address range specified should be mapped into user mode rather than kernel mode. This flag is meaningful only when VIDEO_MEMORY_SPACE_IO is not set.

VirtualAddress

Is a handle to the process into which the memory must be mapped, or NULL. NULL specifies that the port driver should map the logical memory range at any location in the address space of the current process. Otherwise, this handle can be a value passed in a VRP by the miniport driver's corresponding display driver. On return from a successful call, VideoPortMapBankedMemory resets the variable to the base virtual address to which it has mapped the given PhysicalAddress.

BankLength

Specifies the size of a bank, in bytes.

ReadWriteBank

If set to TRUE the bank is Read\Write; if set to FALSE there are two independent read and write banks.

BankRoutine

Pointer to a driver-supplied HwVidBankedMemoryCallback function to be called by the Memory Manager when a new bank is accessed by the display driver.

Context

Pointer to a miniport driver-supplied context that is passed back to the driver when the BankRoutine is called.

Return value

VideoPortMapBankedMemory returns NO_ERROR if the given logical range was successfully mapped to a user-space virtual range. Otherwise, it can return ERROR_INVALID_PARAMETER.

Remarks

VideoPortMapBankedMemory runs in kernel mode within the same context as the user-mode thread that initiated the call.

VideoPortMapBankedMemory is called by miniport drivers to efficiently manage x86 type devices that are limited to mapping a frame buffer in banks. When this routine returns to the caller, the frame buffer managed by the miniport driver is mapped as a linear frame buffer into the address space of the requesting process (see VirtualAddress parameter). When an access is made to an address in that mapped space, the Memory Manager calls the miniport driver to update the Bank Index Register to point to a new bank that contains the currently referenced address. The Bank Index Register is maintained by the miniport driver in BankRoutine. The correct Bank Index is calculated by the Memory Manager transparently to a display driver and passed to the miniport driver in the callback to BankRoutine.

Requirements

Requirement	Value
Minimum supported client	Available in Windows 2000 and later versions of the Windows operating systems.
Target Platform	Desktop
Header	video.h (include Video.h)
Library	Videoprt.lib
DLL	Videoprt.sys
IRQL	PASSIVE_LEVEL