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=-13.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 66AC1C433F5 for ; Thu, 9 Sep 2021 14:53:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CA4B6108B for ; Thu, 9 Sep 2021 14:53:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235176AbhIIOyW (ORCPT ); Thu, 9 Sep 2021 10:54:22 -0400 Received: from mga14.intel.com ([192.55.52.115]:59540 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236798AbhIIOyQ (ORCPT ); Thu, 9 Sep 2021 10:54:16 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10101"; a="220486530" X-IronPort-AV: E=Sophos;i="5.85,280,1624345200"; d="scan'208";a="220486530" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2021 07:53:02 -0700 X-IronPort-AV: E=Sophos;i="5.85,280,1624345200"; d="scan'208";a="450002774" Received: from njani-mobl1.gar.corp.intel.com ([10.213.113.5]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 Sep 2021 07:52:57 -0700 Message-ID: <9586d66802138dc144836b310ef5b20394c59695.camel@linux.intel.com> Subject: Re: [PATCH] cpufreq: intel_pstate: Override parameters if HWP forced by BIOS From: Srinivas Pandruvada To: Doug Smythies Cc: "Rafael J. Wysocki" , Len Brown , Linux Kernel Mailing List , Linux PM list Date: Thu, 09 Sep 2021 07:52:54 -0700 In-Reply-To: References: <20210909034802.1708-1-dsmythies@telus.net> <223a72d91cfda9b13230e4f8cd6a29f853535277.camel@linux.intel.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.40.0-1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2021-09-09 at 06:30 -0700, Doug Smythies wrote: > On Wed, Sep 8, 2021 at 11:33 PM Srinivas Pandruvada > wrote: > > > > On Wed, 2021-09-08 at 20:48 -0700, Doug Smythies wrote: > > > If HWP has been already been enabled by BIOS, it may be > > > necessary to override some kernel command line parameters. > > > Once it has been enabled it requires a reset to be disabled. > > > > > > Signed-off-by: Doug Smythies > > > --- > > >  drivers/cpufreq/intel_pstate.c | 22 ++++++++++++++++------ > > >  1 file changed, 16 insertions(+), 6 deletions(-) > > > > > > diff --git a/drivers/cpufreq/intel_pstate.c > > > b/drivers/cpufreq/intel_pstate.c > > > index bb4549959b11..073bae5d4498 100644 > > > --- a/drivers/cpufreq/intel_pstate.c > > > +++ b/drivers/cpufreq/intel_pstate.c > > > @@ -3267,7 +3267,7 @@ static int __init intel_pstate_init(void) > > >                  */ > > >                 if ((!no_hwp && > > > boot_cpu_has(X86_FEATURE_HWP_EPP)) || > > >                     intel_pstate_hwp_is_enabled()) { > > > -                       hwp_active++; > > > +                       hwp_active = 1; > > Why this change? > > It was just to keep it at 1, but I agree not absolutely needed. > > > > > >                         hwp_mode_bdw = id->driver_data; > > >                         intel_pstate.attr = hwp_cpufreq_attrs; > > >                         intel_cpufreq.attr = hwp_cpufreq_attrs; > > > @@ -3347,17 +3347,27 @@ device_initcall(intel_pstate_init); > > > > > >  static int __init intel_pstate_setup(char *str) > > >  { > > > +       /* > > > +        * If BIOS is forcing HWP, then parameter > > > +        * overrides might be needed. Only print > > > +        * the message once, and regardless of > > > +        * any overrides. > > > +        */ > > > +       if(!hwp_active > > This part of code is from early_param, Is it possible that > > hwp_active is not 0? > > Not at this point, in any testing I did. > But I do not know the authoritative answer > to your question. > But as you explained you want to prevent repeated print of "HWP enabled by BIOS". So you need this. > > > > > && boot_cpu_has(X86_FEATURE_HWP)) > > > +               if(intel_pstate_hwp_is_enabled()){ > > > +                       pr_info("HWP enabled by BIOS\n"); > > > +                       hwp_active = 1; > > > +               } > > >         if (!str) > > >                 return -EINVAL; > > > > > > -       if (!strcmp(str, "disable")) > > > +       if (!strcmp(str, "disable") && !hwp_active) > > >                 no_load = 1; > > > -       else if (!strcmp(str, "active")) > > > +       if (!strcmp(str, "active")) > > >                 default_driver = &intel_pstate; > > > -       else if (!strcmp(str, "passive")) > > > +       if (!strcmp(str, "passive")) > > >                 default_driver = &intel_cpufreq; > > > > Why "else if" changed to "if" ? > > Because it doesn't matter anyway and I would > have had to figure out another qualifier. > This way, and given that this executes once per > intel_pstate command line parameter, the code > executes the way it used to, overall. If someone specified intel_pstate=active, it will also compare with "passive" with this change. Thanks, Srinivas > > > > > > > Thanks, > > Srinivas > > > > > - > > > -       if (!strcmp(str, "no_hwp")) { > > > +       if (!strcmp(str, "no_hwp") && !hwp_active) { > > >                 pr_info("HWP disabled\n"); > > >                 no_hwp = 1; > > >         } > > > >