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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=unavailable 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 7A53DC2BA83 for ; Wed, 12 Feb 2020 12:07:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5739820714 for ; Wed, 12 Feb 2020 12:07:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725874AbgBLMHe (ORCPT ); Wed, 12 Feb 2020 07:07:34 -0500 Received: from mx2.suse.de ([195.135.220.15]:34028 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726470AbgBLMHd (ORCPT ); Wed, 12 Feb 2020 07:07:33 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 5B0F3AD2C; Wed, 12 Feb 2020 12:07:32 +0000 (UTC) Date: Wed, 12 Feb 2020 13:07:01 +0100 From: Jean Delvare To: Mika Westerberg Cc: "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org, Wim Van Sebroeck , Guenter Roeck , linux-watchdog@vger.kernel.org, Tom Abraham Subject: Re: [PATCH 3/3] ACPI / watchdog: Set default timeout in probe Message-ID: <20200212130701.1682e406@endymion> In-Reply-To: <20200212110540.83559-3-mika.westerberg@linux.intel.com> References: <20200211180331.11dbe525@endymion> <20200212110540.83559-1-mika.westerberg@linux.intel.com> <20200212110540.83559-3-mika.westerberg@linux.intel.com> Organization: SUSE Linux X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-watchdog-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-watchdog@vger.kernel.org On Wed, 12 Feb 2020 14:05:40 +0300, Mika Westerberg wrote: > If the BIOS default timeout for the watchdog is too small userspace may > not have enough time to configure new timeout after opening the device > before the system is already reset. For this reason program default > timeout of 30 seconds in the driver probe and allow userspace to change > this from command line or through module parameter (wdat_wdt.timeout). > > Reported-by: Jean Delvare > Signed-off-by: Mika Westerberg > --- > drivers/watchdog/wdat_wdt.c | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c > index 2132018f031d..7b0257163522 100644 > --- a/drivers/watchdog/wdat_wdt.c > +++ b/drivers/watchdog/wdat_wdt.c > @@ -54,6 +54,13 @@ module_param(nowayout, bool, 0); > MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" > __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); > > +#define WDAT_DEFAULT_TIMEOUT 30 > + > +static int timeout = WDAT_DEFAULT_TIMEOUT; > +module_param(timeout, int, 0); > +MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" > + __MODULE_STRING(WDAT_DEFAULT_TIMEOUT) ")"); > + > static int wdat_wdt_read(struct wdat_wdt *wdat, > const struct wdat_instruction *instr, u32 *value) > { > @@ -308,6 +315,7 @@ static int wdat_wdt_probe(struct platform_device *pdev) > struct device *dev = &pdev->dev; > const struct acpi_wdat_entry *entries; > const struct acpi_table_wdat *tbl; > + int default_timeout = timeout; > struct wdat_wdt *wdat; > struct resource *res; > void __iomem **regs; > @@ -438,6 +446,22 @@ static int wdat_wdt_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, wdat); > > + /* > + * Set initial timeout so that userspace has time to configure > + * the watchdog properly after it has opened the device. In some > + * cases the BIOS default is too short and causes immediate reboot. > + */ > + default_timeout = timeout; You have already done that at variable declaration time. > + if (timeout < wdat->wdd.min_hw_heartbeat_ms || > + timeout > wdat->wdd.max_hw_heartbeat_ms) Comparing seconds to milliseconds is unlikely to give the expected result. > + default_timeout = WDAT_DEFAULT_TIMEOUT; > + else > + default_timeout = timeout; You have already done that twice ;-) > + > + ret = wdat_wdt_set_timeout(&wdat->wdd, timeout); You must pass "default_timeout" here, not "timeout", else the check before serves no purpose. It might be less confusing to not introduce a separate variable and just tweak timeout in place? > + if (ret) > + return ret; > + > watchdog_set_nowayout(&wdat->wdd, nowayout); > return devm_watchdog_register_device(dev, &wdat->wdd); > } -- Jean Delvare SUSE L3 Support