From: Uwe Kleine-König Date: Mon, 11 Apr 2011 08:59:09 +0000 (+0200) Subject: serial/imx: read cts state only after acking cts change irq X-Git-Tag: v2.6.35.13~19 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=617a954d482ca5c165da9ec8345a02a23fbaab78;p=thirdparty%2Fkernel%2Fstable.git 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and acking the irq (USR1_RTSD) the last edge doesn't generate an irq and uart_handle_cts_change is called with a outdated value for cts.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 Tested-by: Arwed Springer Signed-off-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c index eacb588a93459..6d2028e996ada 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);