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=DKIM_SIGNED,DKIM_VALID, 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 E2331C33CB2 for ; Wed, 15 Jan 2020 19:00:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BAD6224671 for ; Wed, 15 Jan 2020 19:00:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ragnatech-se.20150623.gappssmtp.com header.i=@ragnatech-se.20150623.gappssmtp.com header.b="1Po/Nr5g" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729146AbgAOTAq (ORCPT ); Wed, 15 Jan 2020 14:00:46 -0500 Received: from mail-lf1-f65.google.com ([209.85.167.65]:37177 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729021AbgAOTAq (ORCPT ); Wed, 15 Jan 2020 14:00:46 -0500 Received: by mail-lf1-f65.google.com with SMTP id b15so13552874lfc.4 for ; Wed, 15 Jan 2020 11:00:44 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ragnatech-se.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=kkSb5XFjVAdxecaVMhl5npWQb18A0fEroSSW8nmnqso=; b=1Po/Nr5guIuj6JQYoyc/KkE2nefZ1byRnzhIL0cZAsK3RGvI3fJkEkY/bGk0cTkAd0 kDWjA6dRSCzLUtSg//R1d2EBfjBhdbpy5H1KiaHH1kh8p3Za2iyUn4CGU9Nju9vPFfC5 WeFvK9LySoUYs9HGaIQxIQGPcXYWRxFXbUUzo6hTSHUfZzdR/0/FGYs2H14kVKEa/5Zb y3zne2qaISLAtJbrG4ZY4akS/967WJ/+TdjfJQau7TTugw1S2gsGvLSUGgwazUk24DgN 7qUWFg9CIRCNw3+tn5upPxxwCMTDxLKaptys5FaGYqqeg3VLsSVcLBPtpql+Es9depwN wwAA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=kkSb5XFjVAdxecaVMhl5npWQb18A0fEroSSW8nmnqso=; b=SES6k9J92gloBobl/a9jduJvQhoqqe3QXXA6AJJM0btzqaD+2afdKjy66+Sl0TqmzL JfWl1IBgqpt8ZMz9y+Mnko4pPWeavo5LQQMZ87pQ9KO6X4SdZ191yAfb9DfEvj2q2qXs PJ1ggY7Vqq+609FxVTspgKcsU9L+F+rl/UNA9bMGJwXR2v2EQxH4TjC+b+DlJd17nVyQ ZF4emWpob2sH62PBsPF3tTfVsb5czYaEOFjTNO+k4dwFwn8eK6Jrd1MtdsqX94a2QNjp 1bSDrYKzlUxk6+ND/hQCCzRuU466inZA82m6OHhzY1E7rWxFU4/GaEuLjTSnFs7nCkLx k2Tw== X-Gm-Message-State: APjAAAX8WYE+uAO6DTEWRN2pwuF5HSOXQlLpWPtvbjD/8ZWu+EG7Wq2H x/ScuGKdkLQYInNuD5c0L6ZxKw== X-Google-Smtp-Source: APXvYqwbotwNaG3js+/LSjbpf1LJM+qnAsB5qH1RGXygA8dGWsziSSyAsUNJzuGJL5tdkzmeUhMdXw== X-Received: by 2002:ac2:50da:: with SMTP id h26mr235067lfm.80.1579114843968; Wed, 15 Jan 2020 11:00:43 -0800 (PST) Received: from localhost (h-93-159.A463.priv.bahnhof.se. [46.59.93.159]) by smtp.gmail.com with ESMTPSA id y29sm9522204ljd.88.2020.01.15.11.00.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jan 2020 11:00:43 -0800 (PST) Date: Wed, 15 Jan 2020 20:00:42 +0100 From: Niklas =?iso-8859-1?Q?S=F6derlund?= To: Daniel Lezcano Cc: linux-pm@vger.kernel.org, Wolfram Sang , linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH 1/2] thermal: rcar_thermal: Remove temperature bound Message-ID: <20200115190042.GB979534@oden.dyn.berto.se> References: <20200114222945.3128250-1-niklas.soderlund+renesas@ragnatech.se> <20200114222945.3128250-2-niklas.soderlund+renesas@ragnatech.se> <20200115134559.GA945270@oden.dyn.berto.se> <20200115183940.GA979534@oden.dyn.berto.se> <710eeff0-e8f4-5f03-836a-6a2e87e415e8@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <710eeff0-e8f4-5f03-836a-6a2e87e415e8@linaro.org> Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On 2020-01-15 19:52:25 +0100, Daniel Lezcano wrote: > On 15/01/2020 19:39, Niklas Söderlund wrote: > > Hi Daniel, > > > > On 2020-01-15 19:15:11 +0100, Daniel Lezcano wrote: > >> On 15/01/2020 14:45, Niklas Söderlund wrote: > >>> Hi Daniel, > >>> > >>> Thanks for your feedback. > >>> > >>> On 2020-01-15 14:24:30 +0100, Daniel Lezcano wrote: > >>>> On 14/01/2020 23:29, Niklas Söderlund wrote: > >>>>> The hardware manual states that the operation of the sensor is not > >>>>> guaranteed outside the range of -40°C to 125°C, not that the readings > >>>>> are invalid. Remove the bound check and try to deliver temperature > >>>>> readings even if we are outside the guaranteed operation range. > >>>> > >>>> And what if the sensor is returning crap in this out-of-range operation? > >>> > >>> I'm not sure what is worse, reporting an untrue (but still outside the > >>> guaranteed operation range) extreme temperature or failing with -EIO. > >>> The view of the hardware guys is that it's better to report what the > >>> sensor indicates then to return -EIO. > >> > >> I don't get the point. > >> > >> What happens if we read the sensor while it is above or below the limits? > > > > The manual describes the read outs as being +/- 2°C from the true > > temperature for the guaranteed operating range. Outside this range the > > difference between the true temperature and the read out temperature > > might be larger than 2°C. > > Ok, I see the point now. I guess in any case the SoC won't be working > very well outside of these operating range also. > > It would be interesting to add in the core code a warning when reaching > the sensor's operating range. Please replace the code deletion in your > patches by a comment keeping the range values for reference if we add a > sensor boundaries property later. Thanks, will do and post a v2. > > Thanks > -- Daniel > > -- > Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: Facebook | > Twitter | > Blog > -- Regards, Niklas Söderlund