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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08531C433EF for ; Fri, 8 Oct 2021 13:05:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFBAF61037 for ; Fri, 8 Oct 2021 13:05:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242168AbhJHNHN (ORCPT ); Fri, 8 Oct 2021 09:07:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230262AbhJHNHK (ORCPT ); Fri, 8 Oct 2021 09:07:10 -0400 Received: from mail-oi1-x229.google.com (mail-oi1-x229.google.com [IPv6:2607:f8b0:4864:20::229]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4DA58C061570; Fri, 8 Oct 2021 06:05:15 -0700 (PDT) Received: by mail-oi1-x229.google.com with SMTP id z11so13678708oih.1; Fri, 08 Oct 2021 06:05:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:to:cc:references:from:subject:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=NwsrAhEELdrD0yf4RSjEr+rJMAn0uIiuidWlamL/LOY=; b=PXybhPRq+OocRcXM0uT95Rqd+6ho1ULptdg17EqaD9MOH284R2N2Jp61anXiO9EXNw gcxYQJ4LKqL9nDCIkZP9o3MFX0FXe+ilzb99+XiDeOGQUmG5+lE6860016W/NEbAMrIQ VAdEcSUBD1eJpDBMIh+2HNNkA0j6SqavnPaP82DDb9Cn363WOVo2jqZR+QS4ho1q1ZFk cWYWSCeUD8n407i2uKMgq46DEzHpAPZYXwtn35SGQGLS/Igec17zBEsHnD5EqIbTTzd7 fZgW3AeGYbNB8ZLmPtNRFCH+iOgnaD8cMcDFxCnnZESImELw4MxJn0hSbP4dvxmHTRZE xK+g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:to:cc:references:from:subject:message-id :date:user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=NwsrAhEELdrD0yf4RSjEr+rJMAn0uIiuidWlamL/LOY=; b=LQ1Dqe5GxS0plzfIcZze9NApLZUx8mXbSE9rbHz872BVXRFTDJnYAgW+6I7y92sLCw JYgnu+q5hZ7PhyXZ0yeL5nn/Dj8/dOlG3ckXojhvBTuAtTn7g36jc7Pyu+Ug8HzIf9+n 3vZW3SHfWhZdVCu92jdgDGVMhpqWyfrmzJa3D160MW8fG63HKdXc59L+JjOqIQmSbEAe 3X2LgqCK6rNDgyZonGd2Hq5GgvRQ5bq/S9eUXCcYMK6se9gwwODCb3WhI8pjd4LZFvdm 75JCvCc9JQSLx+rJnH2kobkIAz2ZKpjog9SMHRNenwxvRkNqH9QDCu9mQz2ZrLsZEnh4 Wz3Q== X-Gm-Message-State: AOAM532RpQzIYlaLRcW5qrKadCmVOBrJIS8bIiCBfZWDWYWkgK/sNZBR yEP5OKyc+jJ2QMH8ywlCe6IYeCDpLBU= X-Google-Smtp-Source: ABdhPJzAgwXcB0KHIplrVqdpfaS8VOmrwW848F9e71enp8VB33pR/GG9zLflWD7oktfsLxaZ3F2PDQ== X-Received: by 2002:a05:6808:118c:: with SMTP id j12mr7746018oil.65.1633698314656; Fri, 08 Oct 2021 06:05:14 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id 63sm343194oih.14.2021.10.08.06.05.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 Oct 2021 06:05:13 -0700 (PDT) Sender: Guenter Roeck To: Jan Kiszka , Wim Van Sebroeck Cc: linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?Q?Mantas_Mikul=c4=97nas?= , "Javier S . Pedro" References: <20211008003302.1461733-1-linux@roeck-us.net> <9b9c797c-04f1-0ccf-b6fe-e9f1e4f5c17d@siemens.com> From: Guenter Roeck Subject: Re: [PATCH] Revert "watchdog: iTCO_wdt: Account for rebooting on second timeout" Message-ID: <66dece5d-d2e2-c3e0-3d7a-565385fe5003@roeck-us.net> Date: Fri, 8 Oct 2021 06:05:12 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 MIME-Version: 1.0 In-Reply-To: <9b9c797c-04f1-0ccf-b6fe-e9f1e4f5c17d@siemens.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/8/21 12:52 AM, Jan Kiszka wrote: > On 08.10.21 02:33, Guenter Roeck wrote: >> This reverts commit cb011044e34c ("watchdog: iTCO_wdt: Account for >> rebooting on second timeout") and commit aec42642d91f ("watchdog: iTCO_wdt: >> Fix detection of SMI-off case") since those patches cause a regression >> on certain boards (https://bugzilla.kernel.org/show_bug.cgi?id=213809). >> >> While this revert may result in some boards to only reset after twice >> the configured timeout value, that is still better than a watchdog reset >> after half the configured value. >> >> Fixes: cb011044e34c ("watchdog: iTCO_wdt: Account for rebooting on second timeout") >> Fixes: aec42642d91f ("watchdog: iTCO_wdt: Fix detection of SMI-off case") >> Cc: Jan Kiszka >> Cc: Mantas Mikulėnas >> Reported-by: Javier S. Pedro >> Signed-off-by: Guenter Roeck >> --- >> drivers/watchdog/iTCO_wdt.c | 12 +++--------- >> 1 file changed, 3 insertions(+), 9 deletions(-) >> >> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c >> index 643c6c2d0b72..ced2fc0deb8c 100644 >> --- a/drivers/watchdog/iTCO_wdt.c >> +++ b/drivers/watchdog/iTCO_wdt.c >> @@ -71,8 +71,6 @@ >> #define TCOBASE(p) ((p)->tco_res->start) >> /* SMI Control and Enable Register */ >> #define SMI_EN(p) ((p)->smi_res->start) >> -#define TCO_EN (1 << 13) >> -#define GBL_SMI_EN (1 << 0) >> >> #define TCO_RLD(p) (TCOBASE(p) + 0x00) /* TCO Timer Reload/Curr. Value */ >> #define TCOv1_TMR(p) (TCOBASE(p) + 0x01) /* TCOv1 Timer Initial Value*/ >> @@ -357,12 +355,8 @@ static int iTCO_wdt_set_timeout(struct watchdog_device *wd_dev, unsigned int t) >> >> tmrval = seconds_to_ticks(p, t); >> >> - /* >> - * If TCO SMIs are off, the timer counts down twice before rebooting. >> - * Otherwise, the BIOS generally reboots when the SMI triggers. >> - */ >> - if (p->smi_res && >> - (inl(SMI_EN(p)) & (TCO_EN | GBL_SMI_EN)) != (TCO_EN | GBL_SMI_EN)) >> + /* For TCO v1 the timer counts down twice before rebooting */ >> + if (p->iTCO_version == 1) >> tmrval /= 2; >> >> /* from the specs: */ >> @@ -527,7 +521,7 @@ static int iTCO_wdt_probe(struct platform_device *pdev) >> * Disables TCO logic generating an SMI# >> */ >> val32 = inl(SMI_EN(p)); >> - val32 &= ~TCO_EN; /* Turn off SMI clearing watchdog */ >> + val32 &= 0xffffdfff; /* Turn off SMI clearing watchdog */ >> outl(val32, SMI_EN(p)); >> } >> >> > > Sigh, how broken is this architecture of the iTCO? Agreed, this leaves > no option then. > > BTW, the fact that we saw an inconsistency in read-back timeout > indicates that there is still an issue for the remaining /= 2 case > (means v1), but I'm loosing interest in fixing those issues, given how > hard it is to test broadly without breaking users first. > Agreed. This is because the /=2 handling is only implemented in iTCO_wdt_set_timeout() without matching code in iTCO_wdt_get_timeleft(). I don't have hardware to test, so I am not going to touch that code myself. We can address that if/when someone reports the actual problem and has the ability to test a fix. Thanks, Guenter