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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7F6F2C47087 for ; Fri, 28 May 2021 21:10:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54C1661378 for ; Fri, 28 May 2021 21:10:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229494AbhE1VMQ (ORCPT ); Fri, 28 May 2021 17:12:16 -0400 Received: from mail.kernel.org ([198.145.29.99]:52384 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229481AbhE1VMQ (ORCPT ); Fri, 28 May 2021 17:12:16 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id C8A286135F; Fri, 28 May 2021 21:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1622236240; bh=tx2umF6VdeBuQF/vmjtZNIWlHOVomeoBoB1YfMXQjXo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ZQh7fmeLG1fLD0NjrhPVc0/nf5AflXWxxdqos1yvK4i+ARcC1gRhRyVuQHK8sNSax jiw4wFfPP/EIOxACNt4S9PS0E0xGxFgU3y4hTwz0zLqHO6GMwdHvk+ch4wWCMe0HhJ PYcUJpJRMw3Xu1CAyX2b5HjgwRiDJt60T0r4yhpA7zxZKwqsjyOSMb3gTwrPea3mLI Jp8nye5VlCjmW/+0yLdRbkF/CG53AksL3WhmkdYPWG8h2zt4AZcc52uWwX4j9A0ETJ mb+s3eQjP12chDMWWklYvHpMJ/73Beyr+PQC9Tog24Qj1TvmCVk03JwECLlMBHaPIg aSAq7hAKYKy3w== Received: by pali.im (Postfix) id 13F3BB0B; Fri, 28 May 2021 23:10:37 +0200 (CEST) Date: Fri, 28 May 2021 23:10:37 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: Armin Wolf Cc: linux@roeck-us.net, jdelvare@suse.com, linux-hwmon@vger.kernel.org Subject: Re: [PATCH v2 6/6] hwmon: (dell-smm-hwmon) Update docs Message-ID: <20210528211037.2tnblovgb3rkcwnq@pali> References: <20210528173716.10975-1-W_Armin@gmx.de> <20210528173716.10975-7-W_Armin@gmx.de> <20210528175310.53ey6xq5ttpfkod6@pali> <90260e4f-7e3f-20af-7706-add965ae9192@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <90260e4f-7e3f-20af-7706-add965ae9192@gmx.de> User-Agent: NeoMutt/20180716 Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org On Friday 28 May 2021 22:37:06 Armin Wolf wrote: > Am 28.05.21 um 19:53 schrieb Pali Rohár: > > On Friday 28 May 2021 19:37:16 W_Armin@gmx.de wrote: > > > From: Armin Wolf > > > > > > pwm1_enable is now readable too. > > Hello! pwm1_enable cannot be readable. It is write-only node. See also: > > https://lore.kernel.org/linux-hwmon/201605221717.26604@pali/ > > > Hello, > > in Documentation/hwmon/sysfs-interface, pwmX_enable is marked as RW, and the document also states that > "Read/write values may be read-only for some chips, depending on the hardware implementation", so i > thought that pwm1_enable being WO is a violation of that rule. I know that hwmon sysfs are rw but if driver cannot provide correct read value then it is better to do not report it. > Also i belive the i8kutils are not calling SMM anymore, so can we just leave a note saying something like > "this value is cached and is not correct when using certain userspace tools which disable/enable BIOS fan control"? Well, maybe state changed in time (it is 5 years since that email) but there are still more older versions of i8k userspace tools and some of them used to issue SMM calls. Personally, I have used them (prior introducing kernel support) and I can expect that other people who wrote other scripts may have them in their inittab (or converted to systemd equivalent). So it is better to not expect that something is not used. Whole SMM stuff is fragile for various reasons... Also another issue is that initial value is unknown. Because we do not know if BIOS fan control is enabled or disabled. I was told that in past BIOS fan control was old Dell laptops was disabled, so if people adds old laptops into whilelist it would mean that we even do not guess state of BIOS fan control status. > > > Signed-off-by: Armin Wolf > > > --- > > > Documentation/hwmon/dell-smm-hwmon.rst | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/Documentation/hwmon/dell-smm-hwmon.rst b/Documentation/hwmon/dell-smm-hwmon.rst > > > index 3bf77a5df995..d6fe9b8a2c40 100644 > > > --- a/Documentation/hwmon/dell-smm-hwmon.rst > > > +++ b/Documentation/hwmon/dell-smm-hwmon.rst > > > @@ -35,7 +35,7 @@ Name Perm Description > > > fan[1-3]_input RO Fan speed in RPM. > > > fan[1-3]_label RO Fan label. > > > pwm[1-3] RW Control the fan PWM duty-cycle. > > > -pwm1_enable WO Enable or disable automatic BIOS fan > > > +pwm1_enable RW Enable or disable automatic BIOS fan > > > control (not supported on all laptops, > > > see below for details). > > > temp[1-10]_input RO Temperature reading in milli-degrees > > > -- > > > 2.20.1 > > > >