NdisMFreeMapRegisters

This function releases a set of map registers that were allocated during initialization with NdisMAllocateMapRegisters by a busmaster DMA NIC driver.

At a Glance

Header file:	Ndis.h
Windows CE versions:	2.0 and later

Syntax

VOID NdisMFreeMapRegisters(
IN NDIS_HANDLE MiniportAdapterHandle );

Parameters

MiniportAdapterHandle: Handle originally input to the MiniportInitialize function.

Remarks

If it has already made a successful call to the NdisMAllocateMapRegisters function, the NIC driver of a busmaster DMA device calls this function if any of the following occurs:

Its MiniportInitialize function is unable to initialize the NIC, so this function must release all existing claims on hardware resources for that NIC before it returns control.
The NIC for which the miniport allocated the map registers is being removed.
The driver is being unloaded, either because the system is shutting down or because the user reconfigured the network components used in the machine.

As soon as it calls this function, the driver of a busmaster DMA NIC can no longer use the map registers that it previously allocated.

This function can be called only from an NIC driver’s MiniportInitialize and MiniportHalt functions.

A driver that calls this function runs at IRQL PASSIVE_LEVEL.