From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 013F817BA3; Mon, 18 Nov 2024 01:29:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731893394; cv=none; b=HHa2K9b/w2C0cp2I3ut7kcDjlhK/aiVc5dQgJE8qQb0N0sX+YdizfriwjL1XWYE+w+lrtrLt7WiixtlfS2SjvkopoxPSyAa9pxbJ99f5lD2P2Enwmrtk+XaYtdh5qjrPOe5T7UCp7GXzg0HEs4xKK9VF8C/C8vAuW7eucJWAmt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731893394; c=relaxed/simple; bh=lM9XoLTlH4w7aBEstkNtGMfmVvVr+vxFBznR54ornks=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=BJtIqxzeVeUxaeTZ1EZ6jKFh78/8POUOzD5um2mkc90WKMMJE/cbI+hqUPfKsVFv/pm7Q0hnV/Fl6RmjonGY093jbFRG0UtYkq8Lr/UPXi2ADmA02la7fjcvF1yXO5Cm/igWCdsWVeRt8F0Xr02yPtlZ0CmmzU4HdNPJ5YBMg1g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.105]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Xs93019Fwz10Rt3; Mon, 18 Nov 2024 09:27:08 +0800 (CST) Received: from dggemv704-chm.china.huawei.com (unknown [10.3.19.47]) by mail.maildlp.com (Postfix) with ESMTPS id 93C8F1403A0; Mon, 18 Nov 2024 09:29:43 +0800 (CST) Received: from kwepemn100009.china.huawei.com (7.202.194.112) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 18 Nov 2024 09:29:43 +0800 Received: from [10.67.121.59] (10.67.121.59) by kwepemn100009.china.huawei.com (7.202.194.112) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Mon, 18 Nov 2024 09:29:42 +0800 Message-ID: Date: Mon, 18 Nov 2024 09:29:42 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v2] ACPI: thermal: Support for linking devices associated with the thermal zone To: "Rafael J. Wysocki" CC: , , , , , , References: <20241113085634.7657-1-lihuisong@huawei.com> <52539572-6128-8c87-84e6-3f539d887b34@huawei.com> From: "lihuisong (C)" In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To kwepemn100009.china.huawei.com (7.202.194.112) 在 2024/11/14 19:53, Rafael J. Wysocki 写道: > Hi, > > On Thu, Nov 14, 2024 at 9:37 AM lihuisong (C) wrote: >> Hi Rafael, >> >> 在 2024/11/13 17:26, Rafael J. Wysocki 写道: >>> On Wed, Nov 13, 2024 at 10:07 AM Huisong Li wrote: >>>> There are many 'cdevX' files which link cooling devices under >>>> '/sys/class/thermal/thermal_zoneX/'. These devices contain active cooling >>>> devices and passive cooling devices. And user cann't directly know which >>>> devices temperature is represented by the thermal zone. >>>> >>>> However, ACPI spec provides a '_TZD' object which evaluates to a package >>>> of device names. Each name corresponds to a device in the ACPI namespace >>>> that is associated with the thermal zone. The temperature reported by the >>>> thermal zone is roughly correspondent to that of each of the devices. >>>> >>>> User can get all devices a thermal zone measured by the 'measures' >>>> directory under the thermal zone device. >>> Well, that's kind of clear, but what exactly is the use case? Why >>> does the user need to know that? >> IMO, this makes thermal zone information more friendly. >> For instance, user can directly know the temperature of CPUs or other >> devices is roughly represented by which thermal zone. >> This may offer the convenience for further usersapce application. >> >> BTW, the '_TZD' method is similar to the '_PMD' in acpi power meter. >> Since ACPI spec provides them, they should also have a role in their >> existence. > So there is no specific use case, but it is possible that somebody may > want to use this information, IIUC. > > Well, let's defer making kernel changes until there is a user > wanting/needing this information. Then we'll decide how to expose it. > > For one, I'm not convinced that exposing it under the ACPI > representation of a thermal zone is going to be really useful. All right. Thanks for your review. > > .