PAGP_FREE_VIRTUAL - NtDoc
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headers
// videoagp.h
PAGP_FREE_VIRTUAL PagpFreeVirtual;
VOID PagpFreeVirtual(
[in] IN PVOID HwDeviceExtension,
[in] IN PVOID VirtualReserveContext,
[in] IN ULONG Pages,
[in] IN ULONG Offset
)
{...}
View the official Windows Driver Kit DDI referenceNo description available.
The AgpFreeVirtual function frees virtual memory committed by a previous call to AgpCommitVirtual.
HwDeviceExtension [in]Pointer to the miniport driver's device extension.
VirtualReserveContext [in]Identifies a reserved virtual address range. This context handle was obtained from AgpReserveVirtual.
Pages [in]Specifies the number of pages of virtual memory that the video port driver should unmap.
Offset [in]Specifies the page offset into the reserved virtual address range identified by VirtualReserveContext that indicates the actual base address at which to unmap virtual memory.
When a miniport driver calls AgpFreeVirtual, Pages pages of virtual addresses are unmapped. The unmapped range begins Offset pages into the range associated with VirtualReserveContext. The miniport driver must specify that the exact offset and number of pages be freed as were committed in a prior call to AgpCommitVirtual.
A call to AgpFreeVirtual must be paired with a previous call to AgpCommitVirtual, and that call to AgpCommitVirtual must be preceded by a successful call to AgpReserveVirtual. If AgpReserveVirtual fails (returns NULL), you must not call AgpCommitVirtual or AgpFreeVirtual.