To force loading on Oracle Sun X86 servers, provide one kernel command line
parameter
intel_pstate = force
For those who be aware of the risk of no power capping capabily working and
try to get better performance with this driver.
Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
Tested-by: Alexey Kodanev <alexey.kodanev@xxxxxxxxxx>
---
v2: change to hardware vendor specific naming parameter.
v4: refine code and doc.
v5&v6: fix a typo in doc.
v7: change enum PCC to PPC.
v8: change the name of kernel command line parameter to generic one.
Documentation/kernel-parameters.txt | 5 +++++
drivers/cpufreq/intel_pstate.c | 6 +++++-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 479f332..7d0983e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1446,6 +1446,11 @@ 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
+ force
+ Enable intel_pstate on systems where it may cause problems to
+ happen due to conflicts with platform firmware attempting to
+ drive P-states by itself in certain situations (for thermal
+ control or power capping in general or other purposes).
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 1bb62ca..2654e13 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -866,6 +866,7 @@ static struct cpufreq_driver intel_pstate_driver = {
};
static int __initdata no_load;
+static unsigned int force_load;
static int intel_pstate_msrs_not_valid(void)
{
@@ -1003,7 +1004,8 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
case PSS:
return intel_pstate_no_acpi_pss();
case PPC:
- return intel_pstate_has_acpi_ppc();
+ return intel_pstate_has_acpi_ppc() &&
+ (!force_load);
}
}
@@ -1078,6 +1080,8 @@ static int __init intel_pstate_setup(char *str)
if (!strcmp(str, "disable"))
no_load = 1;
+ if (!strcmp(str, "force"))
+ force_load = 1;
return 0;
}
early_param("intel_pstate", intel_pstate_setup);
--
1.8.3.1
--
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