From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Nelson Subject: Re: [PATCH] serial: imx: Disable new features of autobaud detection Date: Wed, 14 May 2014 12:38:11 -0700 Message-ID: <5373C623.4030203@boundarydevices.com> References: <1400093703-10128-1-git-send-email-festevam@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pb0-f41.google.com ([209.85.160.41]:62153 "EHLO mail-pb0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751126AbaENTiQ (ORCPT ); Wed, 14 May 2014 15:38:16 -0400 Received: by mail-pb0-f41.google.com with SMTP id uo5so20083pbc.28 for ; Wed, 14 May 2014 12:38:15 -0700 (PDT) In-Reply-To: <1400093703-10128-1-git-send-email-festevam@gmail.com> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Fabio Estevam , gregkh@linuxfoundation.org Cc: troy.kisky@boundarydevices.com, shawn.guo@freescale.com, kernel@pengutronix.de, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Fabio Estevam On 05/14/2014 11:55 AM, Fabio Estevam wrote: > From: Fabio Estevam > > Bit 7 of UCR3 is described in the i.MX reference manuals (with the exception > of i.MX1) as follows: > > ADNIMP: Autobaud Detection Not Improved-. Disables new features of > autobaud detection (See Baud Rate Automatic Detection > Protocol, for more details). > > 0 Autobaud detection new features selected > 1 Keep old autobaud detection mechanism > > The "new features" mechanism occasionally cause the receiver to get out of sync > and continuously produce received characters of '\xff'. > > In order to reproduce the problem: > > $ stty -F /dev/ttymxc0 19200 > > - Change the terminal baudrate to 19200 > > - Type in the console and it should look good > > - Change the terminal baudrate back to 115200 > > - Type 'b' in the console, then a stream of garbage characters is seen. > > Also rename the bit definition as per the reference manual. > > Tested on mx6q, mx6dl, mx6solo and mx53. > > Based on a patch from Eric Nelson for U-boot. > > Signed-off-by: Fabio Estevam > --- > drivers/tty/serial/imx.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > Tested-by: Eric Nelson