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=-5.3 required=3.0 tests=BAYES_00, 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 4BD9FC46466 for ; Mon, 5 Oct 2020 16:48:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F5DF2100A for ; Mon, 5 Oct 2020 16:48:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727571AbgJEQsO (ORCPT ); Mon, 5 Oct 2020 12:48:14 -0400 Received: from mail1.bemta23.messagelabs.com ([67.219.246.115]:44786 "EHLO mail1.bemta23.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726772AbgJEQsO (ORCPT ); Mon, 5 Oct 2020 12:48:14 -0400 Received: from [100.112.4.31] (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256 bits)) by server-4.bemta.az-c.us-east-1.aws.symcld.net id 4C/B1-22503-B4E4B7F5; Mon, 05 Oct 2020 16:48:11 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrCKsWRWlGSWpSXmKPExsWSLveKTdfbrzr e4MlebYtJM/4zW+y/LmHRtdDAYuH9U6wWX7/dZrd4c3w6k8Xyff2MFpd3zWGz+Nx7hNGiqbMJ yOqYzGKxes8LZou1X+axOfB6TJo5g9lj56y77B6/tq1h8di8Qstj3slAj562TUwe7/ddZfP4v EkugCOKNTMvKb8igTXjy5pV7AWXOCtmz/jO0sD4ib2LkYtDSOA/o8TDi92sEM5zRolPL1czdT FycAgLZEtMeynXxcjJISJQLLF30hWwBmaBlSwSl/o/MkE0tDNLbGiaww5SxSagLbFlyy82EJt XwFai894aVhCbRUBFYsK3b4wgtqhAhMSa4xOZIGoEJU7OfMICYnMKxEr09R8Fq2EWsJCYOf88 lC0ucevJfCYIW15i+9s5zCC2hICCxKz2newQdoLEspd3mCcwCs5CMnYWklGzkIyahWTUAkaWV YymSUWZ6RkluYmZObqGBga6hoZGuma6ZhZ6iVW6yXqlxbqpicUluoZ6ieXFesWVuck5KXp5qS WbGIERmlLA5rKDccmbD3qHGCU5mJREebV8quOF+JLyUyozEosz4otKc1KLDzFqcHAIXDl4ZDa jFEtefl6qkgTvVJA6waLU9NSKtMwcYBKBKZXg4FES4a0DSfMWFyTmFmemQ6ROMSpKifMeBUkI gCQySvPg2mCJ6xKjrJQwLyMDA4MQT0FqUW5mCar8K0ZxDkYlYd633kBTeDLzSuCmvwJazAS0+ PbRCpDFJYkIKakGpn25tw8sXFR2KkDBVnDzFf7Fkz3U9yVPfLnhp7lPk1+K3CvGtgelKV5izK n2Xhv+X6vuv5JUk+rqxbfsmdvdcxN6LD4q6h47O6M3OemNzRSvDKVYXdY7KTYKF/ar7L9i21S yOud055ZF8eam215m7VvzRW/PkfM23VeldT4frJp9ruzpZE6D6t986w+X8ISr5Pr/jnkz+eK9 uc//XPvE8mflixBL9mzb5SfKhGU97EvL53ywuXNpQk3wB8HJTu5VLkxH1zkYzq9htjZKj72lN /H4QY9jNjuWs59yZRWZ6idYqXB2CXuDG0tRR/vZt3YxAV7aV9OWmtnX8qtue5086Y/08w9nHp w8a7I2+v21NUosxRmJhlrMRcWJAKLfq7/XAwAA X-Env-Sender: markpearson@lenovo.com X-Msg-Ref: server-54.tower-406.messagelabs.com!1601916489!1091018!1 X-Originating-IP: [103.30.234.6] X-SYMC-ESS-Client-Auth: outbound-route-from=pass X-StarScan-Received: X-StarScan-Version: 9.60.3; banners=-,-,- X-VirusChecked: Checked Received: (qmail 22615 invoked from network); 5 Oct 2020 16:48:11 -0000 Received: from unknown (HELO lenovo.com) (103.30.234.6) by server-54.tower-406.messagelabs.com with ECDHE-RSA-AES256-GCM-SHA384 encrypted SMTP; 5 Oct 2020 16:48:11 -0000 Received: from reswpmail04.lenovo.com (unknown [10.62.32.23]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by Forcepoint Email with ESMTPS id A167F9EC14C539EDC414; Tue, 6 Oct 2020 00:48:06 +0800 (CST) Received: from localhost.localdomain (10.46.54.144) by reswpmail04.lenovo.com (10.62.32.23) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2044.4; Mon, 5 Oct 2020 09:47:58 -0700 Subject: Re: [External] RE: [RFC] Documentation: Add documentation for new performance_profile sysfs class To: "Limonciello, Mario" , =?UTF-8?Q?Barnab=c3=a1s_P=c5=91cze?= CC: Hans de Goede , Darren Hart , Andy Shevchenko , Mark Gross , Mark Pearson , Elia Devito , Bastien Nocera , Benjamin Berg , "linux-pm@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "platform-driver-x86@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20201003131938.9426-1-hdegoede@redhat.com> <20201003131938.9426-2-hdegoede@redhat.com> From: Mark Pearson Message-ID: <91a9bb74-49e7-0a8d-cbc1-3f1907293fa4@lenovo.com> Date: Mon, 5 Oct 2020 12:47:56 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.46.54.144] X-ClientProxiedBy: reswpmail04.lenovo.com (10.62.32.23) To reswpmail04.lenovo.com (10.62.32.23) Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 2020-10-05 12:11 p.m., Limonciello, Mario wrote: >> >> Excuse my ignorance, but I don't really see why this interface would be tied >> to >> ACPI devices? Why is it not possible to write a driver that implements this >> interface >> and directly modifies device registers? Am I missing something obvious here? >> > > When implemented for the two vendors mentioned here, it would be using a > proprietary "firmware API" implemented by those two vendors. For example write > arguments (0x1, 0x2) to ACPI-WMI method WMFT and it will cause firmware to coordinate > using undisclosed protocol to affect the platform changes desirable. > > This is different in my mind from "kernel writes to a specific register" to set > power properties of a specific device. > Just curious on this point - isn't that (mostly) what all hardware does? You write to it and the device does "stuff" to achieve the required effect. Yes this is in proprietary firmware, but from my experience with hardware devices that's not uncommon these days anyway. Let me know if I'm misunderstanding something here. I couldn't see the difference between a register written to via ACPI and one written to via some other protocol (SMBUS? or whatever) Mark