Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1952110AbdDYR2U (ORCPT ); Tue, 25 Apr 2017 13:28:20 -0400 Received: from mail-out.m-online.net ([212.18.0.10]:47151 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1952088AbdDYR2L (ORCPT ); Tue, 25 Apr 2017 13:28:11 -0400 X-Auth-Info: qAAOC+x7USgdF6R8cQKFytPDeZszhZChGa4EBh0F2Xk= Subject: Re: [PATCH] ARM: dts: imx6sx-sdb: Remove cpufreq OPP override To: Leonard Crestez , Fabio Estevam References: <89cc7192100bdc9ce546bf6000446e629457ebc1.1493138693.git.leonard.crestez@nxp.com> <1493141004.3557.8.camel@nxp.com> Cc: Shawn Guo , Sascha Hauer , Peter Chen , Anson Huang , "linux-pm@vger.kernel.org" , Viresh Kumar , "Rafael J. Wysocki" , linux-kernel , Fabio Estevam , "linux-arm-kernel@lists.infradead.org" , Christoph Fritz From: Marek Vasut Message-ID: Date: Tue, 25 Apr 2017 19:28:06 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: <1493141004.3557.8.camel@nxp.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2418 Lines: 59 On 04/25/2017 07:23 PM, Leonard Crestez wrote: > On Tue, 2017-04-25 at 14:02 -0300, Fabio Estevam wrote: >> On Tue, Apr 25, 2017 at 2:02 PM, Fabio Estevam wrote: >>> >>> Hi Leonard, >>> >>> On Tue, Apr 25, 2017 at 1:57 PM, Leonard Crestez >>> wrote: >>>> >>>> The board file for imx6sx-dbg overrides cpufreq operating points to use >>>> higher voltages. This is done because the board has a shared rail for >>>> VDD_ARM_IN and VDD_SOC_IN and when using LDO bypass the shared voltage >>>> needs to be a value suitable for both ARM and SOC. >>>> >>>> This was introduced in: >>>> >>>> commit 54183bd7f766 ("ARM: imx6sx-sdb: add revb board and make it default") >>>> >>>> This only only applies to LDO bypass mode, a feature not present in >>>> upstream. When LDOs are enabled the effect is to use higher voltages than >>>> necesarry for no good reason. >>>> >>>> Setting these higher voltages can make some boards fail to boot with ugly >>>> semi-random crashes, reminiscent of memory corruption. These failures >>>> happen the first time the lowest idle state is used. Remove the OPP >>>> override in order to fix those crashes. >>>> >>>> Signed-off-by: Leonard Crestez >>>> >>>> --- >>>> It's not clear exactly why the crashes happen. Perhaps waking up from idle >>>> draws more power than is available? Removing this override is a correct >>>> change anyway so maybe there is no need to investigate deeper. > >>> Marek just sent a similar one a few minutes ago: >>> http://lists.infradead.org/pipermail/linux-arm-kernel/2017-April/503230.html > >> Forgot to add Marek. > > Wow, that was literally 15 minutes before my patch. In my defense I did > search the archives before starting to format the patch but it had not > arrived yet. Hehehe :-) > Anyway, that version also sets the supply for reg_arm and reg_soc. It > is not necessary for fixing the crash I'm seeing but is good because it > will result in the minimum voltage on VDD_ARM_SOC_IN rather than a fix > 1375mv. I tested Marek's patch and it works fine on my rev B board > (which otherwise fails to boot upstream). Oh that's nice , thanks ! I don't have SDB and I hacked it up after a brief discussion with Fabio without even compile-testing it, thus RFC. Glad to hear it works and thanks for testing it ! Can you add a formal Tested-by please ? -- Best regards, Marek Vasut