WdfDmaTransactionSetMaximumLength - NtDoc
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// wdfdmatransaction.h
VOID WdfDmaTransactionSetMaximumLength(
[in] WDFDMATRANSACTION DmaTransaction,
[in] size_t MaximumLength
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF only]
The WdfDmaTransactionSetMaximumLength method sets the maximum length for the DMA transfers that are associated with a specified DMA transaction.
DmaTransaction [in]A handle to a DMA transaction object that the driver obtained from a previous call to WdfDmaTransactionCreate.
MaximumLength [in]The maximum size, in bytes, that the device can handle in a single DMA transfer operation. If your driver must run on versions of the Microsoft Windows operating systems that support a maximum of 16 map registers, MaximumLength must be less than 65536.
The MaximumLength value applies only to the specified DMA transaction, as follows:
A bug check occurs if the driver supplies an invalid object handle.
Your driver must initialize the DMA transaction before calling WdfDmaTransactionSetMaximumLength.
For information about initializing a DMA transaction, see Creating and Initializing a DMA Transaction.
The following code example sets the maximum transfer length to a driver-defined value, for a specified DMA transaction.
WdfDmaTransactionSetMaximumLength(
dmaTransaction,
MAX_TRANSFER_LENGTH/2,
);