Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750810AbaKUFAv (ORCPT ); Fri, 21 Nov 2014 00:00:51 -0500 Received: from mail-qc0-f169.google.com ([209.85.216.169]:33668 "EHLO mail-qc0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750704AbaKUFAt (ORCPT ); Fri, 21 Nov 2014 00:00:49 -0500 Message-ID: <546EC6FE.1030807@gmail.com> Date: Fri, 21 Nov 2014 00:00:46 -0500 From: Linda Knippers User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Ethan Zhao , Kristen Carlson Accardi CC: Ethan Zhao , "" , "" , "" , "" , "" , "" , "" , "" , "" Subject: Re: [PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC 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> <20141120132317.00ad7210@kcaccard-desk.amr.corp.intel.com> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/20/2014 10:07 PM, Ethan Zhao wrote: > Kristen, > Whatever I would like there is a way to load intel_pstate and give > it a try even it does not support all the PM features. > I think 'force' is OK. > Linda, > Do you like it ? if the 'intel_pstate=force' would force the driver > to be loaded on to HP too ? I'd prefer that it didn't. If you force the intel_pstate driver when the platform thinks it's doing power management, then the OS and the firmware are trying to manage the power at the same time. That's a mess. If you want that for testing or debugging, what are you actually testing or debugging? On an Oracle box, the firmware wouldn't stop doing whatever it's doing just because the intel_pstate driver is loaded, would it? I also wonder what it means to "force" the intel_pstate driver on systems with processors that aren't supported by the intel_pstate driver. It wouldn't really be forced, would it? -- ljk > > Thanks, > Ethan > > On Fri, Nov 21, 2014 at 5:23 AM, Kristen Carlson Accardi > wrote: >> On Thu, 20 Nov 2014 08:57:34 +0800 >> ethan wrote: >> >>> >>> >>>> 在 2014年11月20日，03:05，Kristen Carlson Accardi 写道： >>>> >>>> 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-pm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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/