From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755825AbbCGKjr (ORCPT ); Sat, 7 Mar 2015 05:39:47 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:56207 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753402AbbCGKjn (ORCPT ); Sat, 7 Mar 2015 05:39:43 -0500 Date: Sat, 7 Mar 2015 11:39:39 +0100 From: Pavel Machek To: Sylvain Rochet Cc: Peter Zijlstra , Mark Rutland , Boris Brezillon , Alessandro Zummo , Mike Turquette , Jason Cooper , "rtc-linux@googlegroups.com" , Len Brown , Greg Kroah-Hartman , "linux-pm@vger.kernel.org" , "Rafael J. Wysocki" , "linux-kernel@vger.kernel.org" , Nicolas Ferre , Wim Van Sebroeck , Alexandre Belloni , "linux-serial@vger.kernel.org" , Jean-Christophe Plagniol-Villard , Thomas Gleixner , Jiri Slaby , "linux-arm-kernel@lists.infradead.org" , "linux-watchdog@vger.kernel.org" Subject: Re: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND Message-ID: <20150307103939.GA17964@amd> References: <1425287898-15093-1-git-send-email-boris.brezillon@free-electrons.com> <1425287898-15093-6-git-send-email-boris.brezillon@free-electrons.com> <20150304183809.GD22156@leverpostej> <20150305095306.3db98ac8@bbrezillon> <20150305105308.GA13617@leverpostej> <20150305121723.1da0d016@bbrezillon> <20150305115307.GA14093@leverpostej> <20150307091846.GN23367@worktop.ger.corp.intel.com> <20150307102056.GA28436@gradator.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150307102056.GA28436@gradator.net> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat 2015-03-07 11:20:56, Sylvain Rochet wrote: > Hello, > > On Sat, Mar 07, 2015 at 10:18:46AM +0100, Peter Zijlstra wrote: > > On Thu, Mar 05, 2015 at 11:53:08AM +0000, Mark Rutland wrote: > > > If everyone else is happy with this using IRQF_NO_SUSPEND for now then > > > don't let my comments above block this patch. > > > > Yeah, I'm really not happy with NO_SUSPEND + enable_irq_wake(). > > > > I really want that combo to BUG/WARN -- esp. since there's so much cargo > > culted crap out there. > > > > We should make robust interfaces, not randomly toggle flags until it > > mostly works by accident rather than by design -- which is what this > > feels like. > > > > And while I appreciate the watchdog use-case; I think the easiest > > solution for now is to simply disable the wathdog over suspend until > > we've come up with something that makes sense. > > > > As it is, you need to 'suspend' the watchdog at some point anyhow; you > > don't want that thing to wake you from whatever suspend state you're in. > > The Atmel watchdog can't be stopped once it's started. This is actually > very useful so we can reset if suspend or resume failed, the only > drawback is that you have to wake up from time to time (e.g. by using > the RTC/RTT) to clear the watchdog and then go back to sleep ASAP. Yeah. So you do "echo mem > /sys/power/state", and few seconds/minutes after watchdog kills the system. But you did not ask for dead system, you asked for suspend. And while that behaviour is useful for you, I don't think it is exactly useful behaviour, nor it is the behaviour user would expect. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html