SerCx2SystemDmaTransmitDrainFifoComplete function (sercx.h)

Article
02/22/2024

The SerCx2SystemDmaTransmitDrainFifoComplete method notifies version 2 of the serial framework extension (SerCx2) that the serial controller driver has finished draining the data from the transmit FIFO in the serial controller hardware.

Syntax

void SerCx2SystemDmaTransmitDrainFifoComplete(
  SERCX2SYSTEMDMATRANSMIT SystemDmaTransmit
);

Parameters

SystemDmaTransmit

A SERCX2SYSTEMDMATRANSMIT handle to a PIO-transmit object. The serial controller driver previously called the SerCx2SystemDmaTransmitCreate method to create this object.

Return value

None

Remarks

SerCx2 calls the EvtSerCx2SystemDmaTransmitDrainFifo event callback function, if it is implemented, to drain the transmit FIFO at the end of a system-DMA-transmit transaction. This function makes sure that any data bytes that remain in the FIFO are transmitted from the serial port before SerCx2 completes the write (IRP_MJ_WRITE) request that initiated the transaction. After the last byte is transmitted from the FIFO, the serial controller driver must call the SerCx2SystemDmaTransmitDrainFifoComplete method to notify SerCx2. SerCx2 expects this notification and does not complete the write request until it is notified.

The serial controller must call SerCx2SystemDmaTransmitDrainFifoComplete only in response to a call to the EvtSerCx2SystemDmaTransmitDrainFifo function.

For more information, see SerCx2 System-DMA-Transmit Transactions.

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows 8.1.
Target Platform	Universal
Header	sercx.h
IRQL	<= DISPATCH_LEVEL