diff options
| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2011-04-11 10:59:09 +0200 |
|---|---|---|
| committer | Eric Miao <eric.miao@canonical.com> | 2011-11-10 07:39:02 +0800 |
| commit | 3295abd7d6ccacd8d37a6f4d9b14c134b2cb3554 (patch) | |
| tree | 3d5b1c0e9286fcf6bcd11f861a9e8d3fe3a242e2 | |
| parent | e7ae1fa71713c98625a9dfac084ae7a3548c4e8b (diff) | |
serial/imx: read cts state only after acking cts change irq
commit 5680e94148a86e8c31fdc5cb0ea0d5c6810c05b0 upstream.
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uart_handle_cts_change is called with a outdated value for cts.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>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
(cherry picked from commit 1eb710f4e01a9afab735828c87ef13e2e6b57386)
| -rw-r--r-- | drivers/tty/serial/imx.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 21516c8fa03..531d442415b 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); |