From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756151AbcECPFI (ORCPT ); Tue, 3 May 2016 11:05:08 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:42236 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755635AbcECPFG (ORCPT ); Tue, 3 May 2016 11:05:06 -0400 Subject: Re: [PATCH RFC] Watchdog: sbsa_gwdt: Enhance timeout range To: Guenter Roeck , Pratyush Anand Cc: fu.wei@linaro.org, Suravee.Suthikulpanit@amd.com, wim@iguana.be, linux-arm-kernel@lists.infradead.org, linux-watchdog@vger.kernel.org, open list References: <20da73bb9bdf27993514c1da80fead13dc92932d.1462262900.git.panand@redhat.com> <57289594.3050801@codeaurora.org> <20160503132439.GC13045@dhcppc6.redhat.com> <5728ABE0.5040000@roeck-us.net> <20160503141717.GD13045@dhcppc6.redhat.com> <5728B9BF.8050501@roeck-us.net> From: Timur Tabi Message-ID: <5728BE1B.5010904@codeaurora.org> Date: Tue, 3 May 2016 10:04:59 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:43.0) Gecko/20100101 Firefox/43.0 SeaMonkey/2.40 MIME-Version: 1.0 In-Reply-To: <5728B9BF.8050501@roeck-us.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Guenter Roeck wrote: >> Most likely it will not be corrupted. But, if ISR has been called it >> means >> something went wrong, and watchdog was not kicked for the time >> programmed as >> "timeout". So, probably we should be extra careful. >> > This logic would apply to _every_ watchdog driver implementing interrupts. > Actually, it would apply to _all_ kernel code, and the logic could be used > to introduce hyper-defensive programming all over the place, bloat the > kernel > and ultimately make it all but unusable. I do not believe in such > programming > in an operating system kernel. > > On top of that, the assumption that the kernel would be still sane enough > to call the interrupt handler, but not sane enough to actually execute it, > seems to be a bit far-fetched. Agreed. Pratyush, have you ever seen any watchdog register get corrupted, like you describe? It just seems like you're imagining a problem that has never occurred. -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation collaborative project.