serial: imx: reduce irq-latency after rx overflow

To prevent problems with interrupt latency, and due to the fact, that
the error will be counted anyway (icount.overrun), the dev_err is simply
removed.

Background:
If an rx-fifo overflow occurs a dev_err message was called in interrupt
context. Since dev_err messages are written to console in a synchronous way
(unbuffered), and console may be a serial terminal, this leads to a
highly increased interrupt-latency (several milliseconds).
As a result of the high latency more rx-fifo overflows will happen, and
therefore a feedback loop of errors is created.

Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Acked-By: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 0628fc4841cae99371b4e7bc8b57b6282ecc476a..5b44d53f65b5d986590b048307521c563210cdaa 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -767,7 +767,6 @@ static irqreturn_t imx_int(int irq, void *dev_id)
                writel(USR1_AWAKE, sport->port.membase + USR1);
 
        if (sts2 & USR2_ORE) {
-               dev_err(sport->port.dev, "Rx FIFO overrun\n");
                sport->port.icount.overrun++;
                writel(USR2_ORE, sport->port.membase + USR2);
        }