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=-4.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 94A4BC433DB for ; Mon, 18 Jan 2021 18:36:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 65A8722C9E for ; Mon, 18 Jan 2021 18:36:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393654AbhARSgR (ORCPT ); Mon, 18 Jan 2021 13:36:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407690AbhARSfs (ORCPT ); Mon, 18 Jan 2021 13:35:48 -0500 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2F774C061574; Mon, 18 Jan 2021 10:35:08 -0800 (PST) Received: by mail-lf1-x131.google.com with SMTP id s26so25409335lfc.8; Mon, 18 Jan 2021 10:35:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=IJQ7iXT5ZJJPGjCWc7ZOg3Jpy57FUNGSPots343V6k8=; b=IKNVZurPpwbxQi3xk/Clq+rIAj62XBhEdmVhP58GRiJjUuXEAZslFUxhoa/8kxXvEU gTtDcdLgFaZ0UAPzQYsdeZZzAOMi2CFP5sxEHPxqlrb3zopA1E6hEXeZ4ZY1zqyhioHB 2uG/p2g1rOwbpVotyMsBqBcED5/MKoWGqt8Y4zul52D1FO8tyN0NbdDM/HmJkGQ8Vszn O8RS2tJNi+DAiFEPPyAc+R4t3r03xwTv54Qre2xRNCXq/SV6aF2/dgSFIKOEQMvZHNnG 6zoXZaWQxf+C8IN+x6NPwMn6p4Zo8wj+5/RlNR76i6rmb87HRh2fq1ydUryxJgNr6fwQ 3sfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=IJQ7iXT5ZJJPGjCWc7ZOg3Jpy57FUNGSPots343V6k8=; b=D66WZexjx100P/T29vwEF322empwVZ2/Tadcqri2LI2ZJnkjap5fz8S5SfsuHHubzg SMw/VKj509wVpR2waau+eKf+IZaqQJlfr5/7SSSvNXzDSoZ94F9QzZDrZchkcv7Wgt+B rYta9UPB8lhqzcVVOLk93UQmLZ+cu5uT8CnSXsV2VsSjJElBEIvXCnVyACRV634zyDlm Hv3jFHybWAupzm7ewHl3aZ1LC/5TAoCTQf+GTH/8ge4jXvhB51I9NXTJAK5z8GbLZNkW QLi1Kbsrfl/4ecxFVmjSDLdoTpz2tIvjPuldoRmStnOj7lH7iH0yiEBmEXiPkHCXsZPl VEHQ== X-Gm-Message-State: AOAM530ClZrJZewrkNUHBvf6BWVIAcAWpevQee4+m8I/A+nQGM0Xct9R ybqvHZgsTmddBgK5r09GchamuiATV04= X-Google-Smtp-Source: ABdhPJyZo4KZcV7s56vOT07NUXhRMBh8KcsWPfNtNu+wnqlNtl80pkRMbSaZuOv2tb32jORs1eijvw== X-Received: by 2002:ac2:4a75:: with SMTP id q21mr190165lfp.119.1610994906533; Mon, 18 Jan 2021 10:35:06 -0800 (PST) Received: from [192.168.2.145] (109-252-192-57.dynamic.spd-mgts.ru. [109.252.192.57]) by smtp.googlemail.com with ESMTPSA id w24sm1980365lfl.199.2021.01.18.10.35.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Jan 2021 10:35:05 -0800 (PST) Subject: Re: [PATCH v3 04/12] opp: Add dev_pm_opp_sync_regulators() To: Viresh Kumar Cc: Thierry Reding , Jonathan Hunter , Mark Brown , Liam Girdwood , Ulf Hansson , Peter Geis , Nicolas Chauvet , "Rafael J. Wysocki" , Kevin Hilman , Peter De Schrijver , Viresh Kumar , Stephen Boyd , Nishanth Menon , Yangtao Li , Matt Merhar , linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org References: <20210118005524.27787-1-digetx@gmail.com> <20210118005524.27787-5-digetx@gmail.com> <20210118082013.32y5tndlbw4xrdgc@vireshk-i7> From: Dmitry Osipenko Message-ID: <4acde958-91c1-bbcb-6e20-2d90cf0e57d3@gmail.com> Date: Mon, 18 Jan 2021 21:35:04 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.2 MIME-Version: 1.0 In-Reply-To: <20210118082013.32y5tndlbw4xrdgc@vireshk-i7> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org 18.01.2021 11:20, Viresh Kumar пишет: >> +int dev_pm_opp_sync_regulators(struct device *dev) >> +{ >> + struct opp_table *opp_table; >> + struct regulator *reg; >> + int i, ret = 0; >> + >> + /* Device may not have OPP table */ >> + opp_table = _find_opp_table(dev); >> + if (IS_ERR(opp_table)) >> + return 0; >> + >> + /* Regulator may not be required for the device */ >> + if (!opp_table->regulators) >> + goto put_table; >> + >> + mutex_lock(&opp_table->lock); > What exactly do you need this lock for ? It is needed for protecting simultaneous invocations of dev_pm_opp_sync_regulators() and dev_pm_opp_set_voltage(). The sync_regulators() should be invoked only after completion of the set_voltage() in a case of Tegra power domain driver since potentially both could be running in parallel. For example device driver may be changing performance state in a work thread, while PM domain state is syncing. But maybe it will be better to move the protection to the PM driver since we're focused on sync_regulators() and set_voltage() here, but there are other OPP API functions which use regulators. I'll need to take a closer look at it.