From: Kristen Carlson Accardi <kristen@linux.intel.com>
To: ethan <ethan.kernel@gmail.com>
Cc: Ethan Zhao <ethan.zhao@oracle.com>,
"<dirk.j.brandewie@intel.com>" <dirk.j.brandewie@intel.com>,
"<viresh.kumar@linaro.org>" <viresh.kumar@linaro.org>,
"<rjw@rjwysocki.net>" <rjw@rjwysocki.net>,
"<corbet@lwn.net>" <corbet@lwn.net>,
"<linux-doc@vger.kernel.org>" <linux-doc@vger.kernel.org>,
"<linux-kernel@vger.kernel.org>" <linux-kernel@vger.kernel.org>,
"<linux-pm@vger.kernel.org>" <linux-pm@vger.kernel.org>,
"<joe.jin@oracle.com>" <joe.jin@oracle.com>,
"<brian.maly@oracle.com>" <brian.maly@oracle.com>
Subject: Re: [PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC
Date: Thu, 20 Nov 2014 13:23:17 -0800 [thread overview]
Message-ID: <20141120132317.00ad7210@kcaccard-desk.amr.corp.intel.com> (raw)
In-Reply-To: <41ADCDB8-C204-4661-833B-F68E7D687B61@gmail.com>
On Thu, 20 Nov 2014 08:57:34 +0800
ethan <ethan.kernel@gmail.com> wrote:
>
>
> > 在 2014年11月20日,03:05,Kristen Carlson Accardi <kristen@linux.intel.com> 写道:
> >
> > On Tue, 18 Nov 2014 17:37:06 +0900
> > Ethan Zhao <ethan.zhao@oracle.com> 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 <ethan.zhao@oracle.com>
> >
> > 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 <dirk.j.brandewie@intel.com>");
> >> MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
> >> MODULE_LICENSE("GPL");
> >
next prev parent reply other threads:[~2014-11-20 21:23 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-18 8:36 [PATCH 0/3] intel_pstate: allow to be built as module and handle Sun server power capping Ethan Zhao
2014-11-18 8:37 ` [PATCH 1/3] intel_pstate: skip the driver if Sun server has ACPI _PPC method Ethan Zhao
2014-11-19 20:22 ` Linda Knippers
2014-11-20 0:52 ` ethan
2014-11-20 16:50 ` Dirk Brandewie
2014-11-21 0:37 ` ethan zhao
2014-11-21 4:44 ` Linda Knippers
2014-11-24 1:41 ` ethan zhao
2014-11-24 15:54 ` Linda Knippers
2014-11-25 0:33 ` ethan
2014-11-18 8:37 ` [PATCH 2/3] intel_pstate: allow driver to be built as a module Ethan Zhao
2014-11-18 20:36 ` Rafael J. Wysocki
2014-11-18 8:37 ` [PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC Ethan Zhao
2014-11-18 8:37 ` [PATCH 0/3] intel_pstate: allow to be built as module and handle Sun server power capping Ethan Zhao
2014-11-18 8:37 ` [PATCH 1/3] intel_pstate: skip the driver if Sun server has ACPI _PPC method Ethan Zhao
2014-11-19 14:59 ` Dirk Brandewie
2014-11-20 1:07 ` ethan
2014-11-18 8:37 ` [PATCH 2/3] intel_pstate: allow driver to be built as a module Ethan Zhao
2014-11-19 18:58 ` Kristen Carlson Accardi
2014-11-20 1:01 ` ethan
2014-11-18 8:37 ` [PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC Ethan Zhao
2014-11-19 19:05 ` Kristen Carlson Accardi
2014-11-20 0:57 ` ethan
2014-11-20 21:23 ` Kristen Carlson Accardi [this message]
2014-11-21 3:07 ` Ethan Zhao
2014-11-21 5:00 ` Linda Knippers
2014-11-24 1:56 ` ethan zhao
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