From: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Date: Sat, 20 Jun 2015 17:25:52 +0000 (+0200)
Subject: serial: imx: reduce irq-latency after rx overflow
X-Git-Tag: omap-for-v4.3/fixes-merge-window~43^2~70
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e9b5a9825f6b02a9cf86697bcffafd3d7898f9f6;p=pandora-kernel.git

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>
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