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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B67CC7EE43 for ; Tue, 13 Jun 2023 07:00:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239244AbjFMHAp (ORCPT ); Tue, 13 Jun 2023 03:00:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240373AbjFMHAg (ORCPT ); Tue, 13 Jun 2023 03:00:36 -0400 Received: from mail-lf1-x12f.google.com (mail-lf1-x12f.google.com [IPv6:2a00:1450:4864:20::12f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8AF61730 for ; Tue, 13 Jun 2023 00:00:27 -0700 (PDT) Received: by mail-lf1-x12f.google.com with SMTP id 2adb3069b0e04-4f620583bc2so6156357e87.1 for ; Tue, 13 Jun 2023 00:00:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1686639626; x=1689231626; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=N/wlUBkEwgr5eLaMoxO9Mu5KBKJON7zjaoclqydTonU=; b=BWbka8DnbzJWXRnq1wydHCY2Zd8Enj9c5X4EA/Zc53VMiM6amzlRsGK3qa54mK3mPu x+FJU2DOiTKVenYgWfL1yf7xU5R859nJE2sLd5V6WXIZGd3/ZqF5GLLHccsCiwShdmXe LMsJ9RsxDnyKim+9qckRnb4fY05Zt0FRbcrxC+tOsOWEAwXxOwiXOKVSvqorsydju/uH GeVuJNww6lGNWSB9oE6x/OBVBx73/av7//qn6Bg9mG8Ws4TlupKFD9x3mWUSLiD+4a3x 95rkK6ypdgQKc7gF4K2/nAUs+ONiCIciwG/WN/QPDvcpQ8F0JKyouxRDd4BXx0ZZiVWk Oyrg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686639626; x=1689231626; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=N/wlUBkEwgr5eLaMoxO9Mu5KBKJON7zjaoclqydTonU=; b=Ue1SPBhPJJGi9rFLbaYNpmA2g9TJfR4WMwcxpoD+iG5bA/OQPFQoGQZxQ3+dig2op/ MjUIs2PHDHD2mGsJCbWFzzoLi7aWphpAVQebX+POvUVb8TiWTJ9+EICVzv/k9gtwl5GE X+znh4d1jpy1Wpwa36nGgOui3pxC+SiVL8GkjogIrEN4gwD3WbBaLis1Aq55Y2YCIRN4 dwixtxZu63C3r9pzGUYa+i3YA8Qtmt4Mrhpgjhw/5ohysF2rHxX1wmzI2jv0eLn3BhS0 3exlaETwuOvB4nlVPx1tmMH9saCBOOodmWokNDYGz/wV/kAx3eK9TyfraFeU79vDOZZg 7nLw== X-Gm-Message-State: AC+VfDz8XfiXojZy26+C+YT7uHNUZQ8voV0vKHqVF3mSmlZ7jTuaSSgz fwf+T00h/Lj/oESFn9uWxfszeA== X-Google-Smtp-Source: ACHHUZ75OooZv18bJg2Ru9YdEtkgWO9pEkvBldRwekvqgjfVEd2fYR0q4GdmEufu/J0+Dc1j0wMSug== X-Received: by 2002:a05:6512:ea7:b0:4f4:b397:ebda with SMTP id bi39-20020a0565120ea700b004f4b397ebdamr5164640lfb.56.1686639625978; Tue, 13 Jun 2023 00:00:25 -0700 (PDT) Received: from ?IPV6:2a05:6e02:1041:c10:b5a8:28ff:af00:a97f? ([2a05:6e02:1041:c10:b5a8:28ff:af00:a97f]) by smtp.googlemail.com with ESMTPSA id 11-20020a05600c228b00b003f7361ca753sm13360118wmf.24.2023.06.13.00.00.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Jun 2023 00:00:25 -0700 (PDT) Message-ID: <575f0538-1963-59fa-582f-6686f67b2f29@linaro.org> Date: Tue, 13 Jun 2023 09:00:24 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.11.0 Subject: Re: [PATCH] thermal: Allow selecting the bang-bang governor as default Content-Language: en-US To: Thierry Reding , "Rafael J . Wysocki" Cc: Amit Kucheria , Zhang Rui , linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230609124408.3788680-1-thierry.reding@gmail.com> From: Daniel Lezcano In-Reply-To: <20230609124408.3788680-1-thierry.reding@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/06/2023 14:44, Thierry Reding wrote: > From: Thierry Reding > > For many setups the bang-bang governor is exactly what we want. Many > ARM SoC-based devices use fans to cool down the entire SoC and that > works well only with the bang-bang governor because it uses the > hysteresis in order to let the fan run for a while to cool the SoC > down below the trip point before switching it off again. > > The step-wise governor will behave strangely in these situations. It > doesn't use the hysteresis, so it can lead to situations where the fan > is turned on for only a very brief period and then is switched back off, > only to get switched back on again very quickly because the SoC hasn't > cooled down very much. Applied, thanks -- Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog