From 9522a2ff9cde26ef48c30e0c9ca9ae4dfb669764 Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Wed, 27 Apr 2016 15:48:06 -0700 Subject: cpufreq: intel_pstate: Enforce _PPC limits Use ACPI _PPC notification to limit max P state driver will request. ACPI _PPC change notification is sent by BIOS to limit max P state in several cases: - Reduce impact of platform thermal condition - When Config TDP feature is used, a changed _PPC is sent to follow TDP change - Remote node managers in server want to control platform power via baseboard management controller (BMC) This change registers with ACPI processor performance lib so that _PPC changes are notified to cpufreq core, which in turns will result in call to .setpolicy() callback. Also the way _PSS table identifies a turbo frequency is not compatible to max turbo frequency in intel_pstate, so the very first entry in _PSS needs to be adjusted. This feature can be turned on by using kernel parameters: intel_pstate=support_acpi_ppc Signed-off-by: Srinivas Pandruvada [ rjw: Minor cleanups ] Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/Kconfig.x86 | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/cpufreq/Kconfig.x86') diff --git a/drivers/cpufreq/Kconfig.x86 b/drivers/cpufreq/Kconfig.x86 index c59bdcb83217..adbd1de1cea5 100644 --- a/drivers/cpufreq/Kconfig.x86 +++ b/drivers/cpufreq/Kconfig.x86 @@ -5,6 +5,7 @@ config X86_INTEL_PSTATE bool "Intel P state control" depends on X86 + select ACPI_PROCESSOR if ACPI help This driver provides a P state for Intel core processors. The driver implements an internal governor and will become -- cgit v1.2.3