From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alan Cox <alan@linux.intel.com>, linux-serial@vger.kernel.org
Subject: [PATCH 2/4] serial: 8250_dma: TX optimisation
Date: Wed, 16 Jan 2013 14:08:14 +0200 [thread overview]
Message-ID: <1358338096-32081-3-git-send-email-heikki.krogerus@linux.intel.com> (raw)
In-Reply-To: <1358338096-32081-1-git-send-email-heikki.krogerus@linux.intel.com>
Remove one useless wakeup, and do not use DMA with zero byte
transfers.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
drivers/tty/serial/8250/8250_dma.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 02333fc..b9f7fd2 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -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,
--
1.7.10.4
next prev parent reply other threads:[~2013-01-16 12:07 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-16 12:08 [PATCH 0/4] 8250_dw and 8250_dma fixes Heikki Krogerus
2013-01-16 12:08 ` [PATCH 1/4] serial: 8250_dma: Switch to using tty_port Heikki Krogerus
2013-01-16 12:08 ` Heikki Krogerus [this message]
2013-01-16 12:08 ` [PATCH 3/4] serial: 8250_dw: Use ifdef with ACPI Heikki Krogerus
2013-01-16 12:08 ` [PATCH 4/4] serial: 8250_dw: Set maxburst size Heikki Krogerus
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