PROTECT_WC_MEMORY - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers 
// video.h

PROTECT_WC_MEMORY ProtectWcMemory;

VP_STATUS ProtectWcMemory(
  [in] IN PVOID Context,
  [in] IN PVOID HwDeviceExtension
)
{...}
View the official Windows Driver Kit DDI reference

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Windows Driver Kit DDI reference (nc-video-protect_wc_memory)

PROTECT_WC_MEMORY callback function

Description

The VideoPortProtectWCMemory callback routine protects Write Combined (WC) video memory from being accessed by the CPU.

Parameters

Context [in]

Pointer to a caller-determined context parameter to be passed to the CallbackRoutine. It typically points to the VIDEO_PORT_CONFIG_INFO buffer.

HwDeviceExtension [in]

Pointer to the miniport driver's hardware device extension.

Return value

VideoPortProtectWCMemory returns NO_ERROR if it successfully protects Write Combined video memory; otherwise, it returns an error status of ERROR_INVALID_FUNCTION or ERROR_NOT_ENOUGH_MEMORY.

Remarks

After VideoPortProtectWCMemory is called, the CPU cannot write to Write Combined (WC) memory until the VideoPortRestoreWCMemory callback routine is called.

When WC memory protection is no longer required, the display miniport driver should call VideoPortRestoreWCMemory to restore CPU access to WC memory.

See also

VIDEO_PORT_CONFIG_INFO

VideoPortRestoreWCMemory

View the official Windows Driver Kit DDI reference

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