Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751276AbaKXB4t (ORCPT ); Sun, 23 Nov 2014 20:56:49 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:48407 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750884AbaKXB4r (ORCPT ); Sun, 23 Nov 2014 20:56:47 -0500 Message-ID: <5472904F.8090009@oracle.com> Date: Mon, 24 Nov 2014 09:56:31 +0800 From: ethan zhao Organization: Oracle Corporation User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20130107 Thunderbird/17.0.2 MIME-Version: 1.0 To: Linda Knippers CC: Ethan Zhao , Kristen Carlson Accardi , "" , "" , "" , "" , "" , "" , "" , "" , "" 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> <546EC6FE.1030807@gmail.com> In-Reply-To: <546EC6FE.1030807@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 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 Linda, On 2014/11/21 13:00, Linda Knippers wrote: > > 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? Yes, the platform wouldn't stop doing PM and the SCI even the intel_pstate was loaded. That option just give someone a chance who said "whatever I like intel_pstate On Oracle Servers" > > 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? Yes, wouldn't, such as AMD cpu-id and some old intel CPUs released before SandyBridge. So the best way to to do the 'force' should be specific enough for "Oracle Sun server" Thanks, Ethan > > -- 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/