From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755763AbaIPBni (ORCPT ); Mon, 15 Sep 2014 21:43:38 -0400 Received: from mail-bn1bn0107.outbound.protection.outlook.com ([157.56.110.107]:44226 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754081AbaIPBng (ORCPT ); Mon, 15 Sep 2014 21:43:36 -0400 Date: Tue, 16 Sep 2014 09:43:06 +0800 From: Shawn Guo To: Lucas Stach CC: Robin Gong , , , , , , , , , , Subject: Re: [PATCH v2] ARM: dts: imx6dl: disable dma support for spi on i.mx6dl Message-ID: <20140916014304.GA23450@dragon> References: <1410327012-31185-1-git-send-email-b38343@freescale.com> <1410774073.3314.1.camel@pengutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <1410774073.3314.1.camel@pengutronix.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:192.88.168.50;CTRY:US;IPV:CAL;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(10019020)(6009001)(189002)(51704005)(24454002)(199003)(97756001)(76176999)(97736003)(95666004)(83072002)(86362001)(85852003)(33656002)(33716001)(83506001)(44976005)(6806004)(57986006)(74502001)(46102002)(81542002)(81342002)(80022002)(31966008)(21056001)(74662001)(90102001)(77982001)(46406003)(92566001)(50986999)(105606002)(64706001)(68736004)(110136001)(54356999)(92726001)(23726002)(102836001)(79102001)(87936001)(26826002)(106466001)(50466002)(83322001)(4396001)(84676001)(20776003)(99396002)(104016003)(85306004)(107046002)(76482001)(47776003)(32563001);DIR:OUT;SFP:1102;SCL:1;SRVR:BN1PR03MB038;H:tx30smr01.am.freescale.net;FPR:;MLV:ovrnspm;PTR:InfoDomainNonexistent;MX:1;A:1;LANG:en; X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;UriScan:; X-Forefront-PRVS: 03361FCC43 Authentication-Results: spf=fail (sender IP is 192.88.168.50) smtp.mailfrom=Shawn.Guo@freescale.com; X-OriginatorOrg: freescale.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 15, 2014 at 11:41:13AM +0200, Lucas Stach wrote: > Am Mittwoch, den 10.09.2014, 13:30 +0800 schrieb Robin Gong: > > There is one weird data in rxfifo after one full rx/tx transfer > > done sometimes. It looks a design issue and hard to workaround > > totally, so disable dma functhion here. And will re-enable it > > once the root cause found. > > > Sorry, I'm late to this as Shawn seems to already have picked up this > patch, but this isn't the right way to fix the problem. > > We made it clear at kernel summit last year that we try to not break > existing DTs as booting a new kernel with an old DT is a valid use case. > While you don't strictly violate this rule what you do here is only > fixing systems booting with a new DT while leaving others broken. > > If you are working around a hardware problem please disable DMA support > in the driver. This will also allow you to enable it again, if you find > another workaround without touching the DT again. Okay, it's a valid point. Patch dropped. Shawn