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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 E1B3AC352A2 for ; Wed, 5 Feb 2020 16:38:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BE305217F4 for ; Wed, 5 Feb 2020 16:38:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727466AbgBEQig (ORCPT ); Wed, 5 Feb 2020 11:38:36 -0500 Received: from mga03.intel.com ([134.134.136.65]:4185 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726678AbgBEQig (ORCPT ); Wed, 5 Feb 2020 11:38:36 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2020 08:38:35 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,406,1574150400"; d="scan'208";a="343744237" Received: from lahna.fi.intel.com (HELO lahna) ([10.237.72.163]) by fmsmga001.fm.intel.com with SMTP; 05 Feb 2020 08:38:32 -0800 Received: by lahna (sSMTP sendmail emulation); Wed, 05 Feb 2020 18:38:31 +0200 Date: Wed, 5 Feb 2020 18:38:31 +0200 From: Mika Westerberg To: Guenter Roeck Cc: Jean Delvare , "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org, Wim Van Sebroeck , linux-watchdog@vger.kernel.org, Tom Abraham Subject: Re: Forcing non-ACPI watchdog driver Message-ID: <20200205163831.GG2667@lahna.fi.intel.com> References: <1580915129.23547.3.camel@suse.de> <20200205152435.GE2667@lahna.fi.intel.com> <20200205163048.GD25403@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200205163048.GD25403@roeck-us.net> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On Wed, Feb 05, 2020 at 08:30:48AM -0800, Guenter Roeck wrote: > On Wed, Feb 05, 2020 at 05:24:35PM +0200, Mika Westerberg wrote: > > On Wed, Feb 05, 2020 at 04:05:29PM +0100, Jean Delvare wrote: > > > Hi all, > > > > Hi, > > > > > Is there a way to prevent the ACPI WDAT watchdog interface from being > > > used and force the use of a native watchdog driver instead? > > > > > > I have a customer who reports a regression on kernel upgrade. Old > > > kernel (v4.4) uses iTCO_wdt and watchdog works, new kernel (v4.12) uses > > > wdat_wdt and watchdog doesn't work (instant reboot when opening the > > > device). While I'm going to look for fixes to backport, I think it > > > would be pretty convenient to have a way to just revert to the working > > > driver until the new driver is fixed somehow. But I can't see any way > > > to do that at the moment, short of disabling ACPI completely, which is > > > definitely too extreme to be considered. > > > > > > Am I missing something? > > > > You should be able to revert to iTCO_wdt by simply disabling > > CONFIG_WDAT_WDT from .config. Then acpi_has_watchdog() returns false > > which means that iTCO_wdt is used instead. > > That may not be possible in a generic distribution. Right, they would need to build their own kernel. Currently there is no way to do that without changing .config.