cpufreq: intel_pstate: Enable PPC enforcement for servers
For platforms which are controlled via remove node manager, enable _PPC by
default. These platforms are mostly categorized as enterprise server or
performance servers. These platforms needs to go through some
certifications tests, which tests control via _PPC.
The relative risk of enabling by default is low as this is is less likely
that these systems have broken _PSS table.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 31c094f..1cffa3f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1662,7 +1662,10 @@
Only load intel_pstate on systems which support
hardware P state control (HWP) if available.
support_acpi_ppc
- Enforce ACPI _PPC performance limits.
+ Enforce ACPI _PPC performance limits. If the Fixed ACPI
+ Description Table, specifies preferred power management
+ profile as "Enterprise Server" or "Performance Server",
+ then this feature is turned on by default.
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 31f6ffe..a0823e8 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -347,6 +347,16 @@
#endif
#ifdef CONFIG_ACPI
+
+static bool intel_pstate_get_ppc_enable_status(void)
+{
+ if (acpi_gbl_FADT.preferred_profile == PM_ENTERPRISE_SERVER ||
+ acpi_gbl_FADT.preferred_profile == PM_PERFORMANCE_SERVER)
+ return true;
+
+ return acpi_ppc;
+}
+
/*
* The max target pstate ratio is a 8 bit value in both PLATFORM_INFO MSR and
* in TURBO_RATIO_LIMIT MSR, which pstate driver stores in max_pstate and
@@ -370,7 +380,7 @@
int ret;
int i;
- if (!acpi_ppc)
+ if (!intel_pstate_get_ppc_enable_status())
return;
cpu = all_cpu_data[policy->cpu];