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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 1A89FC433E0 for ; Fri, 3 Jul 2020 10:45:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F2B2D207DA for ; Fri, 3 Jul 2020 10:45:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726098AbgGCKpu (ORCPT ); Fri, 3 Jul 2020 06:45:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725984AbgGCKpu (ORCPT ); Fri, 3 Jul 2020 06:45:50 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD40AC08C5C1; Fri, 3 Jul 2020 03:45:49 -0700 (PDT) Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: andrzej.p) with ESMTPSA id 648AC2A617B Subject: Re: [PATCH v7 00/11] Stop monitoring disabled devices To: Daniel Lezcano , Zhang Rui , linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org Cc: "Rafael J . Wysocki" , Len Brown , Vishal Kulkarni , "David S . Miller" , Jiri Pirko , Ido Schimmel , Johannes Berg , Emmanuel Grumbach , Luca Coelho , Intel Linux Wireless , Kalle Valo , Peter Kaestle , Darren Hart , Andy Shevchenko , Sebastian Reichel , Miquel Raynal , Amit Kucheria , Support Opensource , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , =?UTF-8?Q?Niklas_S=c3=b6derlund?= , Heiko Stuebner , Orson Zhai , Baolin Wang , Chunyan Zhang , Allison Randal , Enrico Weigelt , Gayatri Kammela , Thomas Gleixner , Bartlomiej Zolnierkiewicz , kernel@collabora.com References: <20200629122925.21729-1-andrzej.p@collabora.com> <3d03d1a2-ac06-b69b-93cb-e0203be62c10@collabora.com> <47111821-d691-e71d-d740-e4325e290fa4@linaro.org> <4353a939-3f5e-8369-5bc0-ad8162b5ffc7@linaro.org> <73942aea-ae79-753c-fe90-d4a99423d548@collabora.com> <374dddd9-b600-3a30-d6c3-8cfcefc944d9@linaro.org> <5a28deb7-f307-8b03-faad-ab05cb8095d1@collabora.com> <8aeb4f51-1813-63c1-165b-06640af5968f@linaro.org> <685ef627-e377-bbf1-da11-7f7556ca2dd7@collabora.com> <44c622dd7de8c7bf143c4435c0edd1b98d09a3d6.camel@intel.com> <58265668-fc6d-729a-c126-0c73c2ea853b@linaro.org> From: Andrzej Pietrasiewicz Message-ID: <625911aa-a55f-dcbf-66b3-719117c6aa32@collabora.com> Date: Fri, 3 Jul 2020 12:45:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <58265668-fc6d-729a-c126-0c73c2ea853b@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi, W dniu 03.07.2020 o 08:38, Daniel Lezcano pisze: > On 03/07/2020 03:49, Zhang Rui wrote: >> On Thu, 2020-07-02 at 19:49 +0200, Daniel Lezcano wrote: > > [ ... ] > >>>> So the reason is that ->get_temp() is called while the mutex is >>>> held and >>>> thermal_zone_device_is_enabled() wants to take the same mutex. >>> >>> Yes, that's correct. >>> >>>> Is adding a comment to thermal_zone_device_is_enabled() to never >>>> call >>>> it while the mutex is held and adding another version of it which >>>> does >>>> not take the mutex ok? >>> >>> The thermal_zone_device_is_enabled() is only used in two places, acpi >>> and this imx driver, and given: >>> >>> 1. as soon as the mutex is released, there is no guarantee the >>> thermal >>> zone won't be changed right after, the lock is pointless, thus the >>> information also. >>> >>> 2. from a design point of view, I don't see why a driver should know >>> if >>> a thermal zone is disabled or not >>> >>> It would make sense to end with this function and do not give the >>> different drivers an opportunity to access this information. >> >> I agree. >>> >>> Why not add change_mode for the acpi in order to enable or disable >>> the >>> events >> >> thermal_zone_device_is_enabled() is invoked in acpi thermal driver >> because we only want to do thermal_zone_device_update() when the acpi >> thermal zone is enabled. >> >> As thermal_zone_device_update() can handle a disabled thermal zone now, >> we can just remove the check. > > Ah yes, good point! > > > I sent a short series with fixes. Daniel, can you kindly test it? Regards, Andrzej