Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751359AbbEXQ3n (ORCPT ); Sun, 24 May 2015 12:29:43 -0400 Received: from bh-25.webhostbox.net ([208.91.199.152]:43806 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072AbbEXQ3k (ORCPT ); Sun, 24 May 2015 12:29:40 -0400 Message-ID: <5561FC70.5080802@roeck-us.net> Date: Sun, 24 May 2015 09:29:36 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Timur Tabi , Fu Wei CC: 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 Subject: Re: [PATCH v2 6/7] Watchdog: introduce ARM SBSA watchdog driver References: <=fu.wei@linaro.org> <1432197156-16947-1-git-send-email-fu.wei@linaro.org> <1432197156-16947-7-git-send-email-fu.wei@linaro.org> <555DFCD4.3040701@codeaurora.org> <5560D7AC.50009@codeaurora.org> <5560DCB6.3090008@roeck-us.net> <5561E7EA.5090702@codeaurora.org> <5561F8A8.4080607@codeaurora.org> In-Reply-To: <5561F8A8.4080607@codeaurora.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1726 Lines: 42 On 05/24/2015 09:13 AM, Timur Tabi wrote: > Fu Wei wrote: >> in the first timeout, just panic() maybe not enough, in [RFC] >> version of my patchset, I offer some option as "preaction" to use, but >> for simplifying the first version of driver, I have deleted them. >> but at least, panic() is far more useful than a simple reset. at >> least, it can provide the context of the crashed system to admin. > > My point is that there is very little difference between > > 1) calling panic() on pre-timeout > 2) calling panic() on timeout > The assumption would be that the second timeout doesn't cause a panic but a system reset. > In both cases, the system will panic. The watchdog API says that the system should reset when a timeout occurs, so you cannot call panic() before the timeout expires. > > > If you want to warn user space, that will make driver more > > complicated, I don't think that is a good choose for a first version. > > but we can find a way to improve this later > > In my opinion, this "first version" is not useful. I would like to see a pre-timeout feature that does not panic or reset when a pre-timeout occurs. > The current watchdog API suggests that the pretimeout "allows Linux to record useful information (like panic information and kernel coredumps) before it resets". The call to panic() would be the means to make this happen. Are you suggesting to change this definition ? What should it do instead in your opinion ? Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/