From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752871AbaLEJlI (ORCPT ); Fri, 5 Dec 2014 04:41:08 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:22749 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751232AbaLEJlE (ORCPT ); Fri, 5 Dec 2014 04:41:04 -0500 From: Ethan Zhao To: dirk.j.brandewie@intel.com, kristen@linux.intel.com, linda.knippers@hp.com, viresh.kumar@linaro.org, rjw@rjwysocki.net, corbet@lwn.net Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, ethan.kernel@gmail.com, alexey.kodanev@oracle.com, Ethan Zhao Subject: [PATCH 2/2 V8] intel_pstate: add kernel parameter to force loading. Date: Fri, 5 Dec 2014 18:40:53 +0900 Message-Id: <1417772453-22483-1-git-send-email-ethan.zhao@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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. 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 where it may cause problems to + happen due to conflicts with platform firmware attempting to + drive P-states by itself in certain situations (for thermal + control or power capping in general or other purposes). 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); -- 1.8.3.1