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Commit a3b0397f authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
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serial: 8250_dma: TX optimisation 



Remove one useless wakeup, and do not use DMA with zero byte
transfers.

Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6f3fe3b1

drivers/tty/serial/8250/8250_dma.c

+3 −3
Original line number Diff line number Diff line
@@ -67,12 +67,12 @@ int serial8250_tx_dma(struct uart_8250_port *p) 
	struct circ_buf			*xmit = &p->port.state->xmit;

	struct dma_async_tx_descriptor	*desc;



	if (dma->tx_running) {

		uart_write_wakeup(&p->port);

	if (dma->tx_running)

		return -EBUSY;

	}



	dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);

	if (!dma->tx_size)

		return -EINVAL;



	desc = dmaengine_prep_slave_single(dma->txchan,

					   dma->tx_addr + xmit->tail,