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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 9285FC433EB for ; Tue, 28 Jul 2020 20:41:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 752AC2065C for ; Tue, 28 Jul 2020 20:41:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729224AbgG1UlC (ORCPT ); Tue, 28 Jul 2020 16:41:02 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:50106 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728828AbgG1UlB (ORCPT ); Tue, 28 Jul 2020 16:41:01 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 266ED1C0BEB; Tue, 28 Jul 2020 22:41:00 +0200 (CEST) Date: Tue, 28 Jul 2020 22:40:59 +0200 From: Pavel Machek To: Sumeet Pawnikar Cc: rjw@rjwysocki.net, rui.zhang@intel.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, andriy.shevchenko@intel.com, srinivas.pandruvada@linux.intel.com Subject: Re: [PATCH v2] powercap: Add Power Limit4 support Message-ID: <20200728204059.GF1012@bug> References: <1594715306-10411-1-git-send-email-sumeet.r.pawnikar@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1594715306-10411-1-git-send-email-sumeet.r.pawnikar@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! > Modern Intel Mobile platforms support power limit4 (PL4), which is > the SoC package level maximum power limit (in Watts). It can be used > to preemptively limits potential SoC power to prevent power spikes > from tripping the power adapter and battery over-current protection. > This patch enables this feature by exposing package level peak power > capping control to userspace via RAPL sysfs interface. With this, > application like DTPF can modify PL4 power limit, the similar way > of other package power limit (PL1). > As this feature is not tested on previous generations, here it is > enabled only for the platform that has been verified to work, > for safety concerns. So what happens when the user sets this too high? Battery on fire? Or just sudden poweroff? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html