From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753036AbbFHQKx (ORCPT ); Mon, 8 Jun 2015 12:10:53 -0400 Received: from mail-oi0-f47.google.com ([209.85.218.47]:32934 "EHLO mail-oi0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752392AbbFHQKn (ORCPT ); Mon, 8 Jun 2015 12:10:43 -0400 MIME-Version: 1.0 In-Reply-To: <20150603182503.GD6460@roeck-us.net> References: <=fu.wei@linaro.org> <1433217907-928-1-git-send-email-fu.wei@linaro.org> <1433217907-928-6-git-send-email-fu.wei@linaro.org> <556F4489.6030206@codeaurora.org> <20150603182503.GD6460@roeck-us.net> Date: Tue, 9 Jun 2015 00:10:42 +0800 Message-ID: Subject: Re: [PATCH v4 5/7] Watchdog: introduce ARM SBSA watchdog driver From: Fu Wei To: Guenter Roeck Cc: Timur Tabi , Suravee Suthikulpanit , Linaro ACPI Mailman List , linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Wei Fu , G Gregory , Al Stone , Hanjun Guo , Ashwin Chaugule , Arnd Bergmann , vgandhi@codeaurora.org, wim@iguana.be, Jon Masters , Leo Duran , Jon Corbet , Mark Rutland , Catalin Marinas , Will Deacon , rjw@rjwysocki.net Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Guenter, On 4 June 2015 at 02:25, Guenter Roeck wrote: > On Wed, Jun 03, 2015 at 01:16:41PM -0500, Timur Tabi wrote: >> On 06/01/2015 11:05 PM, fu.wei@linaro.org wrote: >> >+ if (wdd->pretimeout) >> >+ /* The pretimeout is valid, go panic */ >> >+ panic("SBSA Watchdog pre-timeout"); >> >> The problem with this is that WS1 will still occur. So a few seconds after >> the panic() call, the hardware will reset. There won't be any time to debug >> or log anything. >> > > In general the idea here would be to use a crashdump kernel, which, > when loaded, would reset the watchdog before it fires. This kernel > would then write a core dump to a specified location. > > If arm64 doesn't support a crashdump kernel, it might still be possible > to log the backtrace somewhere (eg in nvram using pstore if that is > supported via acpi or efi). yes, you are right , thanks for explaining this. > > Is there reason to believe that this all won't work on arm64 ? I don't think there is a reason. > > Thanks, > Guenter -- Best regards, Fu Wei Software Engineer Red Hat Software (Beijing) Co.,Ltd.Shanghai Branch Ph: +86 21 61221326(direct) Ph: +86 186 2020 4684 (mobile) Room 1512, Regus One Corporate Avenue,Level 15, One Corporate Avenue,222 Hubin Road,Huangpu District, Shanghai,China 200021