[PATCH 3/3] intel_pstate: add module and kernel command line parameter to ignore ACPI _PPC

From: Ethan Zhao
Date: Tue Nov 18 2014 - 03:37:55 EST


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@xxxxxxxxxx>
---
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@xxxxxxxxx>");
MODULE_DESCRIPTION("'intel_pstate' - P state driver Intel Core processors");
MODULE_LICENSE("GPL");
--
1.8.3.1

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