Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759034AbaLKUoU (ORCPT ); Thu, 11 Dec 2014 15:44:20 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:55427 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752783AbaLKUoS (ORCPT ); Thu, 11 Dec 2014 15:44:18 -0500 From: "Rafael J. Wysocki" To: Kristen Carlson Accardi , Ethan Zhao Cc: dirk.j.brandewie@intel.com, linda.knippers@hp.com, viresh.kumar@linaro.org, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, ethan.kernel@gmail.com Subject: Re: [PATCH 2/2 V9] intel_pstate: add kernel parameter to force loading. Date: Thu, 11 Dec 2014 22:05:53 +0100 Message-ID: <2949247.5egUrLMaeB@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <20141210122849.17d258d8@kcaccard-desk.amr.corp.intel.com> References: <1418089399-9310-1-git-send-email-ethan.zhao@oracle.com> <20141210122849.17d258d8@kcaccard-desk.amr.corp.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wednesday, December 10, 2014 12:28:49 PM Kristen Carlson Accardi wrote: > On Tue, 9 Dec 2014 10:43:19 +0900 > Ethan Zhao wrote: > > > To force loading on Oracle Sun X86 servers, provide one kernel command line > > parameter > > > > intel_pstate = force > > > > For those who be aware of the risk of no power capping capabily working and > > try to get better performance with this driver. > > > > Signed-off-by: Ethan Zhao > > Tested-by: Alexey Kodanev > > Reviewed-by: Linda Knippers > > Acked-by: Kristen Carlson Accardi Patch applied, but I had to rebase it on top of the HWP changes from Dirk. Please check my linux-next branch for the result and let me know if there's anything wrong with it. > > --- > > v2: change to hardware vendor specific naming parameter. > > v4: refine code and doc. > > v5&v6: fix a typo in doc. > > v7: change enum PCC to PPC. > > v8: change the name of kernel command line parameter to generic one. > > v9: refine doc > > > > Documentation/kernel-parameters.txt | 5 +++++ > > drivers/cpufreq/intel_pstate.c | 6 +++++- > > 2 files changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > > index 479f332..7d0983e 100644 > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -1446,6 +1446,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > disable > > Do not enable intel_pstate as the default > > scaling driver for the supported processors > > + force > > + Enable intel_pstate on systems that prohibit it by default > > + in favor of acpi-cpufreq. Forcing the intel_pstate driver > > + instead of acpi-cpufreq may disable platform features, such > > + as thermal controls and power capping, that rely on ACPI > > + P-States information being indicated to OSPM and therefore > > + should be used with caution. This option does not work with > > + processors that aren't supported by the intel_pstate driver > > + or on platforms that use pcc-cpufreq instead of acpi-cpufreq. > > > > intremap= [X86-64, Intel-IOMMU] > > on enable Interrupt Remapping (default) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > > index 1bb62ca..2654e13 100644 > > --- a/drivers/cpufreq/intel_pstate.c > > +++ b/drivers/cpufreq/intel_pstate.c > > @@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = { > > }; > > > > static int __initdata no_load; > > +static unsigned int force_load; > > > > static int intel_pstate_msrs_not_valid(void) > > { > > @@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void) > > case PSS: > > return intel_pstate_no_acpi_pss(); > > case PPC: > > - return intel_pstate_has_acpi_ppc(); > > + return intel_pstate_has_acpi_ppc() && > > + (!force_load); > > } > > } > > > > @@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str) > > > > if (!strcmp(str, "disable")) > > no_load = 1; > > + if (!strcmp(str, "force")) > > + force_load = 1; > > return 0; > > } > > early_param("intel_pstate", intel_pstate_setup); > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/