From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S933230AbcFQKDI (ORCPT <rfc822;w@1wt.eu>);
	Fri, 17 Jun 2016 06:03:08 -0400
Received: from mail-wm0-f48.google.com ([74.125.82.48]:35814 "EHLO
	mail-wm0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755371AbcFQKDG convert rfc822-to-8bit (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 17 Jun 2016 06:03:06 -0400
MIME-Version: 1.0
In-Reply-To: <1466101475-8851-1-git-send-email-bjorn.andersson@linaro.org>
References: <1465844571-1229-1-git-send-email-bjorn.andersson@linaro.org> <1466101475-8851-1-git-send-email-bjorn.andersson@linaro.org>
From: Nicolas Dechesne <nicolas.dechesne@linaro.org>
Date: Fri, 17 Jun 2016 13:02:44 +0300
Message-ID: <CAP71WjyPiDK+rr6Z6=Cvp_Bjrpd2HSQ_K58ucJqJ5ZWs_4khtw@mail.gmail.com>
Subject: Re: [PATCH v2] tty: serial: msm: Don't reconfigure same baud rate
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>, Stephen Boyd <sboyd@codeaurora.org>,
        David Brown <david.brown@linaro.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.com>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        linux-soc@vger.kernel.org, linux-serial@vger.kernel.org,
        lkml <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu, Jun 16, 2016 at 9:24 PM, Bjorn Andersson
<bjorn.andersson@linaro.org> wrote:
> msm_set_termios() is called whenever the tty is opened. Setting the baud
> rate requires a full reset of the msm serial block, even when the rate
> is unchanged. In the case when the same uart is used as console this
> reset will discard any console output data still being clocked out of
> the TX fifo.
>
> By skipping the rate-change in the case where the baud rate is unchanged
> since last request we can avoid the reset and the discarding of the
> data.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>


Tested-by: Nicolas Dechesne <nicolas.dechesne@linaro.org>

I no longer see this type of corruption on serial console

[    6.325118] ALSA device �[    6.333338] Freeing unused kernel
memory: 572K (ffffffc000c10000 - ffffffc000c9f000)
[   13.800269]  remoteproc2: remote processor a20400�[  OK  ] Started
Start the WCN core.
[ �         Starting Update UTMP about System Runlevel Changes...