@@ -1662,7 +1662,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
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)
@@ -345,6 +345,16 @@ static struct perf_limits *limits = &powersave_limits;
#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
@@ -368,8 +378,8 @@ static int intel_pstate_init_acpi_perf_limits(struct cpufreq_policy *policy)
int ret;
int i;
- if (!acpi_ppc)
- return 0; /* this is optional flag, so no error returned */
+ if (!intel_pstate_get_ppc_enable_status())
+ return 0; /* this is optional, so no error returned */
cpu = all_cpu_data[policy->cpu];
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> --- Documentation/kernel-parameters.txt | 5 ++++- drivers/cpufreq/intel_pstate.c | 14 ++++++++++++-- 2 files changed, 16 insertions(+), 3 deletions(-)