Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758033AbaKTVXV (ORCPT ); Thu, 20 Nov 2014 16:23:21 -0500 Received: from mga02.intel.com ([134.134.136.20]:55252 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754716AbaKTVXT (ORCPT ); Thu, 20 Nov 2014 16:23:19 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,426,1413270000"; d="scan'208";a="611424466" Date: Thu, 20 Nov 2014 13:23:17 -0800 From: Kristen Carlson Accardi To: ethan Cc: Ethan Zhao , "" , "" , "" , "" , "" , "" , "" , "" , "" Subject: Re: [PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC Message-ID: <20141120132317.00ad7210@kcaccard-desk.amr.corp.intel.com> In-Reply-To: <41ADCDB8-C204-4661-833B-F68E7D687B61@gmail.com> References: <1416299826-15813-1-git-send-email-ethan.zhao@oracle.com> <1416299826-15813-8-git-send-email-ethan.zhao@oracle.com> <20141119110548.24a0a808@kcaccard-desk.amr.corp.intel.com> <41ADCDB8-C204-4661-833B-F68E7D687B61@gmail.com> X-Mailer: Claws Mail 3.10.1 (GTK+ 2.24.24; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=gb2312 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 20 Nov 2014 08:57:34 +0800 ethan wrote: > > > > ?? 2014??11??20?գ?03:05??Kristen Carlson Accardi д???? > > > > On Tue, 18 Nov 2014 17:37:06 +0900 > > Ethan Zhao wrote: > > > >> Add kernel command line parameter > >> intel_pstate = ignore_acpi_ppc > >> and module parameter > >> ignore_acpi_ppc = 1 > >> to allow driver to ignore the ACPI _PPC existence even for Sun x86 servers. > >> These parameter could be used for debug\test\workaround etc purpose. > >> > >> Signed-off-by: Ethan Zhao > > > > What if we used a more generic parameter like "force" that would bypass > > any vendor specific checks and just load anyway? This way we don't have > > to add new parameters everything some new thing shows up that we want to > > ignore. > > > To be honest, I prefer more generic parameter. But to avoid the possible negative affect > To another vendors. I back to this way. Well, your parameter can still impact other vendors as it is. it is pretty typical to assume that using a parameter like "force" means you know what you are doing and accept the risks. Especially if its documented as such. > > Thanks, > Ethan > >> --- > >> Documentation/kernel-parameters.txt | 3 +++ > >> drivers/cpufreq/intel_pstate.c | 8 +++++++- > >> 2 files changed, 10 insertions(+), 1 deletion(-) > >> > >> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > >> index 4c81a86..f502b85 100644 > >> --- a/Documentation/kernel-parameters.txt > >> +++ b/Documentation/kernel-parameters.txt > >> @@ -1446,6 +1446,9 @@ 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 > >> + ignore_acpi_ppc > >> + Ignore the existence of ACPI method _PPC for Sun x86 servers > >> + and load the driver. > >> > >> 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 7c5faea..388387b 100644 > >> --- a/drivers/cpufreq/intel_pstate.c > >> +++ b/drivers/cpufreq/intel_pstate.c > >> @@ -870,6 +870,7 @@ static struct cpufreq_driver intel_pstate_driver = { > >> }; > >> > >> static int __initdata no_load; > >> +static unsigned int ignore_acpi_ppc; > >> > >> static int intel_pstate_msrs_not_valid(void) > >> { > >> @@ -990,7 +991,7 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void) > >> intel_pstate_no_acpi_pss()) > >> return true; > >> if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE) && > >> - intel_pstate_has_acpi_ppc()) > >> + intel_pstate_has_acpi_ppc() && !ignore_acpi_ppc) > >> return true; > >> } > >> > >> @@ -1066,11 +1067,16 @@ static int __init intel_pstate_setup(char *str) > >> > >> if (!strcmp(str, "disable")) > >> no_load = 1; > >> + if (!strcmp(str, "ignore_acpi_ppc")) > >> + ignore_acpi_ppc = 1; > >> return 0; > >> } > >> early_param("intel_pstate", intel_pstate_setup); > >> #endif > >> > >> +module_param(ignore_acpi_ppc, uint, 0644); > >> +MODULE_PARM_DESC(ignore_acpi_ppc, > >> + "value 0 or non-zero. non-zero -> ignore ACPI _PPC and load this driver"); > >> MODULE_AUTHOR("Dirk Brandewie "); > >> MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors"); > >> MODULE_LICENSE("GPL"); > > -- 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/