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From: Huang Shijie <b32955@freescale.com>
To: gregkh@linuxfoundation.org
Cc: linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, shawn.guo@linaro.org,
	Huang Shijie <b32955@freescale.com>
Subject: [PATCH 3/4] serial: imx: fix the wrong number of scatterlist entries when xmit->head is 0
Date: Fri, 11 Oct 2013 18:31:00 +0800	[thread overview]
Message-ID: <1381487461-12850-4-git-send-email-b32955@freescale.com> (raw)
In-Reply-To: <1381487461-12850-1-git-send-email-b32955@freescale.com>

When the (xmit->tail > xmit->head) is true and the xmit->head is 0,
we only need one DMA scatterlist in actually. Current code uses two DMA
scatterlists in this case, this is obviously wrong.

This patch fixes it.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 drivers/tty/serial/imx.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index c6c3b16..cadf7e5 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -532,7 +532,7 @@ static void dma_tx_work(struct work_struct *w)
 		return;
 	}
 
-	if (xmit->tail > xmit->head) {
+	if (xmit->tail > xmit->head && xmit->head > 0) {
 		sport->dma_tx_nents = 2;
 		sg_init_table(sgl, 2);
 		sg_set_buf(sgl, xmit->buf + xmit->tail,
-- 
1.7.2.rc3



WARNING: multiple messages have this Message-ID (diff)
From: b32955@freescale.com (Huang Shijie)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/4] serial: imx: fix the wrong number of scatterlist entries when xmit->head is 0
Date: Fri, 11 Oct 2013 18:31:00 +0800	[thread overview]
Message-ID: <1381487461-12850-4-git-send-email-b32955@freescale.com> (raw)
In-Reply-To: <1381487461-12850-1-git-send-email-b32955@freescale.com>

When the (xmit->tail > xmit->head) is true and the xmit->head is 0,
we only need one DMA scatterlist in actually. Current code uses two DMA
scatterlists in this case, this is obviously wrong.

This patch fixes it.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
 drivers/tty/serial/imx.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index c6c3b16..cadf7e5 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -532,7 +532,7 @@ static void dma_tx_work(struct work_struct *w)
 		return;
 	}
 
-	if (xmit->tail > xmit->head) {
+	if (xmit->tail > xmit->head && xmit->head > 0) {
 		sport->dma_tx_nents = 2;
 		sg_init_table(sgl, 2);
 		sg_set_buf(sgl, xmit->buf + xmit->tail,
-- 
1.7.2.rc3

  parent reply	other threads:[~2013-10-11 10:45 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-11 10:30 [PATCH 0/4] serail: imx: patches for DMA Huang Shijie
2013-10-11 10:30 ` Huang Shijie
2013-10-11 10:30 ` [PATCH 1/4] serial: imx: implement the flush_buffer hook Huang Shijie
2013-10-11 10:30   ` Huang Shijie
2014-06-03  5:51   ` Wang, Jiada (ESD)
2014-06-03  5:51     ` Wang, Jiada (ESD)
2013-10-11 10:30 ` [PATCH 2/4] serial: imx: check the DMA for imx_tx_empty Huang Shijie
2013-10-11 10:30   ` Huang Shijie
2013-10-11 10:31 ` Huang Shijie [this message]
2013-10-11 10:31   ` [PATCH 3/4] serial: imx: fix the wrong number of scatterlist entries when xmit->head is 0 Huang Shijie
2013-10-11 10:31 ` [PATCH 4/4] serial: imx: use the dmaengine_tx_status Huang Shijie
2013-10-11 10:31   ` Huang Shijie

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