From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3023DC2BCA1 for ; Fri, 7 Jun 2019 20:41:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F3218208C3 for ; Fri, 7 Jun 2019 20:41:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Pbx3lnAm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729921AbfFGUlO (ORCPT ); Fri, 7 Jun 2019 16:41:14 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:36766 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729584AbfFGUlO (ORCPT ); Fri, 7 Jun 2019 16:41:14 -0400 Received: by mail-pl1-f195.google.com with SMTP id d21so1255426plr.3; Fri, 07 Jun 2019 13:41:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=ixc2M8woGOIxggbQrFACrPoIu4K++6YKpcQPW8eDSFw=; b=Pbx3lnAm6yRtx72O4losBkUP536cTibHA0OroXdLMJbYHOeTNX+T4zeDQu6HUVs7Pg Qjsnyckoa/CQmlV2Z8SKZeGXOzNbpnrmsXyX7Wu3oKi03XogaQR6CAlC5/hcsaQL6YlS ZPDsWOR61oDTzNOkIuJHfvm3yyxAM1eir0GPXNOAtC69fK1EumxyXW8QJPwswQ3Og8UC OSM5yVM5uxsqMp1lu7Z0F1W00Ra8CHnnKXsWH/1oFTzm0vSC2ws7fdvPa1xZcg+k9uP0 ge8cqWHIORk20tnQeBiUQvHh9iWTyQ22Ky7OXVU000893ntmOO616eSdxVQz2TSW44GV OF6Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=ixc2M8woGOIxggbQrFACrPoIu4K++6YKpcQPW8eDSFw=; b=nSdxglxwmAXn+p5kONvkGlny9S+PV9dW/NyCp4SJNk9nxAggLjrkpWO+Wn5pVVxPVO vMB26Dfrt+/LxA/vCk8I2SmbvHvHCBi5viSdzu+nMreDmY5SwxNrz+5J92YJaYwivisd R9hVzD05+MSuGjHKYmAinNDwjNTClgK7LYHLVwV4W61hZZO8SEXfO3DVHi2nJyIV5E1D ivUCm7Kg7P0ZUgp6yzrQoM7KRf0cMZeSJBlkDiZttvIHx4TRugU7DO4io3v7zoGtr3DT wouZ9w50RhIUN4exf4h1I+3ffCoz8mFy7a5oZPdzk2D7bYNHMt7qNqVg3PVaw8ro/crv 0gUg== X-Gm-Message-State: APjAAAW23VyUozjvj8q7gdYab28/CB7xdxzR7OSGDgSuObH0/MgbPeRM kSb0cqFGNcPx2p6BT5n0IOoDP3qm X-Google-Smtp-Source: APXvYqxQHytqxDxJENMDlRhRcU267VAuufr2xj1Q2aEpPT582KBNbtCm0XCmkt3kps5uEox0V0Mufw== X-Received: by 2002:a17:902:728b:: with SMTP id d11mr28359477pll.78.1559940073691; Fri, 07 Jun 2019 13:41:13 -0700 (PDT) Received: from localhost ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id l8sm3412182pgb.76.2019.06.07.13.41.12 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 07 Jun 2019 13:41:12 -0700 (PDT) Date: Fri, 7 Jun 2019 13:41:11 -0700 From: Guenter Roeck To: Wolfram Sang Cc: Wolfram Sang , linux-watchdog@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Geert Uytterhoeven Subject: Re: [RFC PATCH] watchdog: renesas_wdt: support handover from bootloader Message-ID: <20190607204111.GA19123@roeck-us.net> References: <20190415105201.2078-1-wsa+renesas@sang-engineering.com> <20190524135237.GC15892@kunai> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190524135237.GC15892@kunai> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On Fri, May 24, 2019 at 03:52:37PM +0200, Wolfram Sang wrote: > On Mon, Apr 15, 2019 at 12:52:01PM +0200, Wolfram Sang wrote: > > Support an already running watchdog by checking its enable bit and set > > up the status accordingly before registering the device. > > > > Signed-off-by: Wolfram Sang > > After second thought, I am getting confused a little. If the WDT is > already running then > > a) before this patch: after successful probe, RPM will disable the > clock until userspace opens the watchdog device > > b) after this patch: during probe, our default timeout will be > programmed and because of WDOG_HW_RUNNING, the core will generate pings > until userspace opens the watchdog device. > > So, b) will protect from a crashing kernel (no pings anymore) but not > from something like missing rootfs, or? > > The usecase I had in mind ("give the kernel seconds to boot into > working userspace") seems to be achieved by loading the WDT driver as a > module then, I guess? > Would https://lore.kernel.org/linux-watchdog/20190605140628.618-1-rasmus.villemoes@prevas.dk/ solve your use case ? Guenter