[lkml]   [2011]   [Apr]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    Patch in this message
    Subject[PATCH] [90/106] serial/imx: read cts state only after acking cts change irq
    2.6.35-longterm review patch.  If anyone has any objections, please let me know.

    From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <>

    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    uart_handle_cts_change is called with a outdated value for cts.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 <>

    drivers/serial/imx.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    Index: linux-2.6.35.y/drivers/serial/imx.c
    --- linux-2.6.35.y.orig/drivers/serial/imx.c
    +++ linux-2.6.35.y/drivers/serial/imx.c
    @@ -383,12 +383,13 @@ static void imx_start_tx(struct uart_por
    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);

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at
     \ /
      Last update: 2011-04-26 23:23    [W:0.026 / U:19.488 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site