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authorUwe Kleine-König <u.kleine-koenig@pengutronix.de>2011-04-11 12:59:09 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2011-04-20 03:36:25 +0400
commit5680e94148a86e8c31fdc5cb0ea0d5c6810c05b0 (patch)
tree6830132e5babaf0b39d7b460bff64558fd902467 /drivers/tty/serial/imx.c
parent0f6db2172ffa478409b5facd06bcd38a03b504f7 (diff)
downloadlinux-5680e94148a86e8c31fdc5cb0ea0d5c6810c05b0.tar.xz
serial/imx: read cts state only after acking cts change irq
If cts changes between reading the level at the cts input (USR1_RTSS) and acking the irq (USR1_RTSD) the last edge doesn't generate an irq and uart_handle_cts_change is called with a outdated value for cts. The race was introduced by commit ceca629 ([ARM] 2971/1: i.MX uart handle rts irq) Reported-by: Arwed Springer <Arwed.Springer@de.trumpf.com> Tested-by: Arwed Springer <Arwed.Springer@de.trumpf.com> Cc: stable@kernel.org # 2.6.14+ Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/tty/serial/imx.c')
-rw-r--r--drivers/tty/serial/imx.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index cb36b0d4ef3c..62df72d9f0aa 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -382,12 +382,13 @@ static void imx_start_tx(struct uart_port *port)
static irqreturn_t imx_rtsint(int irq, void *dev_id)
{
struct imx_port *sport = dev_id;
- unsigned int val = readl(sport->port.membase + USR1) & USR1_RTSS;
+ unsigned int val;
unsigned long flags;
spin_lock_irqsave(&sport->port.lock, flags);
writel(USR1_RTSD, sport->port.membase + USR1);
+ val = readl(sport->port.membase + USR1) & USR1_RTSS;
uart_handle_cts_change(&sport->port, !!val);
wake_up_interruptible(&sport->port.state->port.delta_msr_wait);