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| author | Uwe Kleine-König <u.kleine-koenig@pengutronix.de> | 2011-04-11 10:59:09 +0200 |
|---|---|---|
| committer | Andi Kleen <ak@linux.intel.com> | 2011-04-28 08:21:12 -0700 |
| commit | 617a954d482ca5c165da9ec8345a02a23fbaab78 (patch) | |
| tree | 0148eaea903a8471304e5b4bc6603f1a820a7c4f | |
| parent | 0993450a8cccc34704e7375ca47ec555be909b05 (diff) | |
| download | lwn-617a954d482ca5c165da9ec8345a02a23fbaab78.tar.gz lwn-617a954d482ca5c165da9ec8345a02a23fbaab78.zip | |
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uart_handle_cts_change is called with a outdated value for cts.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>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
| -rw-r--r-- | drivers/serial/imx.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c index eacb588a9345..6d2028e996ad 100644 --- a/drivers/serial/imx.c +++ b/drivers/serial/imx.c @@ -383,12 +383,13 @@ 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); |