From patchwork Thu Aug 27 15:10:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. Wysocki" X-Patchwork-Id: 256907 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=-9.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS autolearn=unavailable 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 028CCC433DF for ; Thu, 27 Aug 2020 15:28:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D7A422087D for ; Thu, 27 Aug 2020 15:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727802AbgH0P1w (ORCPT ); Thu, 27 Aug 2020 11:27:52 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:42236 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727815AbgH0P1v (ORCPT ); Thu, 27 Aug 2020 11:27:51 -0400 Received: from 89-64-89-85.dynamic.chello.pl (89.64.89.85) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.459) id 708879f86388fee3; Thu, 27 Aug 2020 17:27:49 +0200 From: "Rafael J. Wysocki" To: Linux PM Cc: Srinivas Pandruvada , LKML , Doug Smythies , Artem Bityutskiy Subject: [PATCH v3 1/5] cpufreq: intel_pstate: Refuse to turn off with HWP enabled Date: Thu, 27 Aug 2020 17:10:42 +0200 Message-ID: <4229182.kmMOFvXRec@kreacher> In-Reply-To: <2240881.fzTuzKk6Gz@kreacher> References: <2240881.fzTuzKk6Gz@kreacher> MIME-Version: 1.0 Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org From: "Rafael J. Wysocki" After commit f6ebbcf08f37 ("cpufreq: intel_pstate: Implement passive mode with HWP enabled") it is possible to change the driver status to "off" via sysfs with HWP enabled, which effectively causes the driver to unregister itself, but HWP remains active and it forces the minimum performance, so even if another cpufreq driver is loaded, it will not be able to control the CPU frequency. For this reason, make the driver refuse to change the status to "off" with HWP enabled. Signed-off-by: Rafael J. Wysocki --- v1 -> v3: No changes --- drivers/cpufreq/intel_pstate.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index e0220a6fbc69..bcda1e700a73 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2716,9 +2716,15 @@ static int intel_pstate_update_status(const char *buf, size_t size) { int ret; - if (size == 3 && !strncmp(buf, "off", size)) - return intel_pstate_driver ? - intel_pstate_unregister_driver() : -EINVAL; + if (size == 3 && !strncmp(buf, "off", size)) { + if (!intel_pstate_driver) + return -EINVAL; + + if (hwp_active) + return -EBUSY; + + return intel_pstate_unregister_driver(); + } if (size == 6 && !strncmp(buf, "active", size)) { if (intel_pstate_driver) {