From patchwork Sat Aug 6 06:15:24 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jean Delvare X-Patchwork-Id: 12937952 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 454A7C19F29 for ; Sat, 6 Aug 2022 06:15:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241680AbiHFGPc (ORCPT ); Sat, 6 Aug 2022 02:15:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60144 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241522AbiHFGPa (ORCPT ); Sat, 6 Aug 2022 02:15:30 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB4ADB876; Fri, 5 Aug 2022 23:15:27 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id AD30C22DAA; Sat, 6 Aug 2022 06:15:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1659766525; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=6LdsyvuXMMZOLuygs1F92G2+lRCOO62r6mwZEfdkrTo=; b=pu3VbbdlryDl5EeEMYkwJS4IKZPG3Ozb0Wq/V3VgyL5FLU0veWsnHM9fKjOrGqIDeae7JJ emBxNPKntZ3ZIBJ9I0Zk7ngWaqyrJpXuCAcdSp2SapoS6155cLJc+OFRVB0DybquufloyA dcG8AAoHT3ra+Ks6N6dacqAZBrcmrKA= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1659766525; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=6LdsyvuXMMZOLuygs1F92G2+lRCOO62r6mwZEfdkrTo=; b=+kSryS+BLiGHuA7lxqDgBP0MfepawUrBu6c0l64YSuRWxz7hUL6tbUyqIExdqaMPwRWfRZ xsKknj3n6+Gx1iCg== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7383613ADE; Sat, 6 Aug 2022 06:15:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id F+FYGv0G7mKmSgAAMHmgww (envelope-from ); Sat, 06 Aug 2022 06:15:25 +0000 Date: Sat, 6 Aug 2022 08:15:24 +0200 From: Jean Delvare To: linux-watchdog@vger.kernel.org, LKML Cc: Wim Van Sebroeck , Guenter Roeck , Mika Westerberg , "Rafael J. Wysocki" Subject: [PATCH v2] watchdog: wdat_wdt: Set the min and max timeout values properly Message-ID: <20220806081524.5636461a@endymion.delvare> Organization: SUSE Linux X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.32; x86_64-suse-linux-gnu) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org The wdat_wdt driver is misusing the min_hw_heartbeat_ms field. This field should only be used when the hardware watchdog device should not be pinged more frequently than a specific period. The ACPI WDAT "Minimum Count" field, on the other hand, specifies the minimum timeout value that can be set. This corresponds to the min_timeout field in Linux's watchdog infrastructure. Setting min_hw_heartbeat_ms instead can cause pings to the hardware to be delayed when there is no reason for that, eventually leading to unexpected firing of the watchdog timer (and thus unexpected reboot). I'm also changing max_hw_heartbeat_ms to max_timeout for symmetry, although the use of this one isn't fundamentally wrong, but there is also no reason to enable the software-driven ping mechanism for the wdat_wdt driver. Signed-off-by: Jean Delvare Fixes: 058dfc767008 ("ACPI / watchdog: Add support for WDAT hardware watchdog") Reviewed-by! Mika Westerberg Cc: Wim Van Sebroeck Cc: Guenter Roeck Cc: Rafael J. Wysocki Reviewed-by: Guenter Roeck --- Changes since v1: * Fix a stupid typo which broke the build. Apparently I shouldn't be sending out patches after midnight, sorry. drivers/watchdog/wdat_wdt.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- linux-5.18.orig/drivers/watchdog/wdat_wdt.c 2022-07-27 07:32:33.336928967 +0200 +++ linux-5.18/drivers/watchdog/wdat_wdt.c 2022-08-06 08:09:49.235935543 +0200 @@ -342,8 +342,8 @@ static int wdat_wdt_probe(struct platfor return -EINVAL; wdat->period = tbl->timer_period; - wdat->wdd.min_hw_heartbeat_ms = wdat->period * tbl->min_count; - wdat->wdd.max_hw_heartbeat_ms = wdat->period * tbl->max_count; + wdat->wdd.min_timeout = DIV_ROUND_UP(wdat->period * tbl->min_count, 1000); + wdat->wdd.max_timeout = wdat->period * tbl->max_count / 1000; wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED; wdat->wdd.info = &wdat_wdt_info; wdat->wdd.ops = &wdat_wdt_ops; @@ -450,8 +450,8 @@ static int wdat_wdt_probe(struct platfor * watchdog properly after it has opened the device. In some cases * the BIOS default is too short and causes immediate reboot. */ - if (timeout * 1000 < wdat->wdd.min_hw_heartbeat_ms || - timeout * 1000 > wdat->wdd.max_hw_heartbeat_ms) { + if (timeout < wdat->wdd.min_timeout || + timeout > wdat->wdd.max_timeout) { dev_warn(dev, "Invalid timeout %d given, using %d\n", timeout, WDAT_DEFAULT_TIMEOUT); timeout = WDAT_DEFAULT_TIMEOUT;