PFREE_DMA_BUFFER_WITH_NOTIFICATION callback function (hdaudio.h)

Article
02/22/2024

The FreeDmaBufferWithNotification routine frees a DMA buffer that was previously allocated by a call to AllocateDmaBufferWithNotification.

The function pointer type for a FreeDmaBufferWithNotification routine is defined as follows.

Syntax

PFREE_DMA_BUFFER_WITH_NOTIFICATION PfreeDmaBufferWithNotification;

NTSTATUS PfreeDmaBufferWithNotification(
  [in] PVOID _context,
  [in] HANDLE Handle,
  [in] PMDL BufferMdl,
  [in] SIZE_T BufferSize
)
{...}

Parameters

[in] _context

Specifies the context value from the Context member of the HDAUDIO_BUS_INTERFACE_V2 structure.

[in] Handle

Handle that identifies the DMA engine. This handle value was obtained from a previous call to AllocateCaptureDmaEngine or AllocateRenderDmaEngine.

[in] BufferMdl

A pointer to the buffer MDL. This value was obtained from a previous call to AllocateDmaBufferWithNotification.

[in] BufferSize

The size of the buffer to be freed. This value was obtained from a previous call to AllocateDmaBufferWithNotification.

Return value

FreeDmaBufferWithNotification returns STATUS_SUCCESS if the call succeeds. Otherwise, FreeDmaBufferWithNotification returns an appropriate error code. The following table shows some of the possible return error codes.

Return code	Description
STATUS_UNSUCCESSFUL	Indicates that the caller is running at an IRQL that is too high.
STATUS_INVALID_HANDLE	Indicates that the handle parameter value is invalid.
STATUS_INVALID_DEVICE_REQUEST	Indicates that the stream is not in the reset state or that no buffer is currently allocated for the DMA engine.

Remarks

The FreeDmaBufferWithNotification routine is used together with the AllocateDmaBufferWithNotification routine. These two routines are available only in the HDAUDIO_BUS_INTERFACE_V2 version of the HD Audio DDI.

Callers of FreeDmaBufferWithNotification must be running at IRQL PASSIVE_LEVEL.

Requirements

Requirement	Value
Minimum supported client	Available in Windows Vista and later versions of Windows.
Target Platform	Desktop
Header	hdaudio.h (include Hdaudio.h)
IRQL	PASSIVE_LEVEL