NdisMQueueDpcEx function (ndis.h)

Article
10/21/2021

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

Syntax

KAFFINITY NdisMQueueDpcEx(
  [in] IN NDIS_HANDLE     NdisInterruptHandle,
  [in] IN ULONG           MessageId,
  [in] IN PGROUP_AFFINITY TargetProcessors,
  [in] IN 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 structure 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 target processors. NDIS should schedule a DPC for each target processor that is indicated in the bitmap. 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 on.

[in] 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

NdisMQueueDpcEx returns a bitmap that indicates target processors. Each bit in the return value identifies a CPU.

NDIS successfully scheduled a DPC for each target processor that is set in the bitmap. 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 on.

If the driver requested a DPC for a CPU, and NDIS indicates that it did not schedule that DPC, then the DPC was not scheduled because the DPC that maps to this interrupt/processor pair was already scheduled for that CPU.

Remarks

NDIS 6.20 and later miniport drivers call NdisMQueueDpcEx to request DPC calls for other processors. NDIS calls the MiniportInterruptDPC or MiniportMessageInterruptDPC function to complete the deferred processing of an interrupt.

NdisMQueueDpcEx is the same as the NdisMQueueDpc function except that the TargetProcessors parameter has a type of KGROUP_AFFINITY. Therefore, NdisMQueueDpcEx can schedule DPCs on processors in any processor group. To schedule DPCs in more than one processor group, you can use multiple calls to NdisMQueueDpcEx.

Note The NdisMQueueDpc, MiniportInterrupt, and MiniportMessageInterrupt functions have a TargetProcessors parameter that is a ULONG. This parameter specifies the first 32 processors in processor group 0.

Important NDIS 6.20 and later drivers should always use NdisMQueueDpcEx to schedule DPCs.

Requirements

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