NdisMQueueDpc function (ndis.h)

Article
10/21/2021

NDIS miniport drivers call the NdisMQueueDpc function to schedule DPC calls on CPUs.

Syntax

ULONG NdisMQueueDpc(
  [in]           NDIS_HANDLE NdisInterruptHandle,
  [in]           ULONG       MessageId,
  [in]           ULONG       TargetProcessors,
  [in, optional] PVOID       MiniportDpcContext
);

Parameters

[in] NdisInterruptHandle

An interrupt handle that the miniport driver obtained in a previous call to the NdisMRegisterInterruptEx function.

[in] MessageId

An MSI message ID for the DPC. If the DPC is for a line-based interrupt, this parameter is not used and it should be set to zero. Otherwise, MessageId is an index to the IO_INTERRUPT_MESSAGE_INFO_ENTRY structures inside a IO_INTERRUPT_MESSAGE_INFO structure. NDIS passes a pointer to the associated IO_INTERRUPT_MESSAGE_INFO structure at the MessageInfoTable member when the driver successfully registers for MSI with the NdisMRegisterInterruptEx function.

[in] TargetProcessors

A bitmap that indicates the target processors for which NDIS should schedule a DPC. Each bit in TargetProcessors identifies a CPU. If the caller sets bit 0, NDIS schedules a DPC for CPU 0. If the caller sets bit 1, NDIS schedules a DPC for CPU 1, and so forth.

[in, optional] MiniportDpcContext

A pointer to a caller-specified context area. NDIS passes this pointer to the MiniportDpcContext parameter of the MiniportInterruptDPC and MiniportMessageInterruptDPC functions.

Return value

NdisMQueueDpc returns a bitmap that indicates the target processors for which NDIS successfully scheduled a DPC. Each bit in the return value identifies a CPU. If NDIS sets bit 0, NDIS scheduled a DPC for CPU 0. If NDIS sets bit 1, NDIS scheduled a DPC for CPU 1, and so forth.

If the driver requested a DPC for a CPU, and NDIS indicates that it did not schedule that DPC, the DPC was not scheduled because a DPC was already scheduled for that CPU.

Remarks

NDIS calls MiniportInterruptDPC or MiniportMessageInterruptDPC to complete the deferred processing of an interrupt. The miniport driver can call NdisMQueueDpc to request additional DPC calls for other processors.

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.0 and 6.1. For NDIS 6.20 and later, use NdisMQueueDpcEx.
Target Platform	Universal
Header	ndis.h (include Ndis.h)
Library	Ndis.lib
IRQL	Any level