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 8B2F0CA0EC1 for ; Mon, 11 Sep 2023 21:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245150AbjIKVIy (ORCPT ); Mon, 11 Sep 2023 17:08:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46922 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242680AbjIKQFq (ORCPT ); Mon, 11 Sep 2023 12:05:46 -0400 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF1661B6 for ; Mon, 11 Sep 2023 09:05:40 -0700 (PDT) Received: by mail-wm1-x331.google.com with SMTP id 5b1f17b1804b1-401b393df02so54241985e9.1 for ; Mon, 11 Sep 2023 09:05:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1694448339; x=1695053139; darn=vger.kernel.org; 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=VBVJ2wHJ2/UKLMCz0YHp9T+QNyQaVPOEmzHr3wHgHAg=; b=iirHIJlj/Q1ROqFAMDiIEBdBoauZRMnmRnc0msgGDaO9EZZmBmn7Cn8dQiejSkxgkl SZ9JPgsKdOXkTdAAs2S7UEldKGnXJ9/ZkaRMc+wWG1VvhrY6I/AoZc5AG3h/P6jjDkew J5WewO4CHKoEHL1E9jttRTqwo877Qj6S7BLSguonSMvbhto+YRaAs/foKBq5Bh+v7RrS wuqoQot43wlKYK9H+9s9GUIBdER6EJVcd4rp0oiR/w+IeYwn73/SLAaiWOUGVzHVMv11 i4Zlmy6lA5S/gOOaT8GgxefdUKiyAQPc/wOQVILBKLVfPQlfGN2O1B4vo8OfuAsabtE1 J9LQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1694448339; x=1695053139; 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=VBVJ2wHJ2/UKLMCz0YHp9T+QNyQaVPOEmzHr3wHgHAg=; b=DZ67T0ODyOvIgdZ9vr2gGc/bXTmSYGoP6fw89VjRyp+5IU730Zbjfc5X94EB3nIJAl 05lpmdwV3lcKxSln6TMZW5ifwrAM3t3TpNI9SWwA2JbcJWwduE7pg9swXabdfpwwJYjt CHl8b7Hlu6Z4y6/H4M9LDn8UR5R5A5KCK2XTDcg1eUtaOlf+/yoe6+eOFdJ4srT1J0gE NIyspvQJBo/cFVpQ7iPUKyNYRvbWBKGBUp7ndXJtx4wwG2P8qOfi/Iik2ES8O1hymO8P JaDkc3/ILLFNQBCglGGieR6i8Qpkl8zGw9XXm04u+x9WJx5wOmsAiTh1WrkJHXuwT+ta fudA== X-Gm-Message-State: AOJu0Yw6+C/WUjW7BvjgeTN0dJqh16/kSVgiFxZlu1J6+6eTVk+E9fuo bnLFIcxrocqjpxoUAsFCpIK9xw== X-Google-Smtp-Source: AGHT+IGyuy2+dN6nVi/A8nEkH5DvEYQPGPUixpXjx1K6xC3tj2xMB32WaeVax7THWg5xlQU35kx7hg== X-Received: by 2002:a05:600c:2116:b0:401:c8b9:4b8a with SMTP id u22-20020a05600c211600b00401c8b94b8amr9091672wml.29.1694448339176; Mon, 11 Sep 2023 09:05:39 -0700 (PDT) Received: from [192.168.1.20] ([178.197.214.188]) by smtp.gmail.com with ESMTPSA id 12-20020a05600c028c00b003fee6e170f9sm10490902wmk.45.2023.09.11.09.05.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 11 Sep 2023 09:05:38 -0700 (PDT) Message-ID: <5f1791b4-78d8-9895-e639-238411b60f00@linaro.org> Date: Mon, 11 Sep 2023 18:05:35 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.0 Subject: Re: [PATCH 04/11] thermal: exynos: remove fine-grained clk management Content-Language: en-US To: Marek Szyprowski , Mateusz Majewski , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org Cc: Rob Herring , Krzysztof Kozlowski , Conor Dooley , Alim Akhtar , Bartlomiej Zolnierkiewicz , "Rafael J. Wysocki" , Daniel Lezcano , Amit Kucheria , Zhang Rui , Liam Girdwood , Mark Brown References: <20230829091853.626011-1-m.majewski2@samsung.com> <20230829091853.626011-5-m.majewski2@samsung.com> From: Krzysztof Kozlowski In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/09/2023 10:40, Marek Szyprowski wrote: > On 29.08.2023 11:56, Krzysztof Kozlowski wrote: >> On 29/08/2023 11:18, Mateusz Majewski wrote: >>> This clock only controls the register operations. The gain in power >>> efficiency is therefore quite dubious, while there is price of added >>> complexity that is important to get right (as a register operation might >>> outright hang the CPU if the clock is not enabled). >> So once it is done right, this stops being argument. The benefit is to >> keep this clock disabled most of the time, which now we lost. >> >> I don't find this patch correct approach. > > I've suggested this change while playing with this driver. > > For me turning AHB clock on/off during normal driver operation seems to > be over-engineering and really gives no real power saving benefits, > especially if thermal driver is the only one that does such fine-grained > clock management (none of the Exynos supported in mainline does that). > Removing it simplifies code and makes it easier to understand or read, > as the current code already was somehow problematic to understand and > unintuitive: > > https://lore.kernel.org/all/c3258cb2-9a56-d048-5738-1132331a157d@linaro.org/ > > Taking into account that the driver is not really maintained, making it > simpler without noticeable feature loss counts as a benefit for me. Hm, ok, let it be, although I bet once someone will come and start adding runtime PM for clock handling... Best regards, Krzysztof