[PATCH 0/7] Add P state driver for Intel Core Processors

From: dirk . brandewie
Date: Tue Feb 05 2013 - 13:26:14 EST

From: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>

This driver implements a scaling driver with an internal governor for
Intel Core processors. The driver follows the same model as the
Transmeta scaling driver (longrun.c) and implements the setpolicy()
instead of target(). Scaling drivers that implement setpolicy() are
assmuned to implement internal governors by the cpufreq core. All the
logic for selecting the current P state is contained within the driver
no external governor is used by the cpufreq core.

At the moment only Intel SandyBridge processors are supported. As
testing on SandyBridge+ processors is completed support will be added
to the driver.

New sysfs files for controlling P state selection have been added to
max_perf_pct: limits the maximum P state that will be requested by
the driver stated as a percentage of the avail performance.

min_perf_pct: limits the minimum P state that will be requested by
the driver stated as a percentage of the avail performance.

no_turbo: limits the driver to selecting P states below the turbo
frequency range.

The units for these for these files are purposely abstract and stated
in terms of available performance and not frequency. In idea that
frequency can be set to a single frequency is a fiction for Intel Core
processors. Even if the scaling driver selects a single P state the
actual frequency the processor will run at is selected by the

This patch set is based on Rafael's bleeding edge branch commit df9d5b7c
Patch 1:
Viresh's patch for the sake of completeness

patch 2-5:
Fix issues related to scaling drivers that implement the
setpolicy() interface instead of target()

patch 6:
Fix cpufreq_stats to handle the scaling driver not exposing a
frequency table while processing CPU_DOWN_PREPARE notification
Patch 7:
The driver itself

Dirk Brandewie (6):
cpufreq: Retrieve current frequency from scaling drivers with
internal governors
cpufreq: Only query drivers that implement cpufreq_driver.target()
cpufreq: Do not track governor name for scaling drivers with internal
cpufreq: balance out cpufreq_cpu_{get,put} for scaling drivers using
cpufreq_stats: do not remove sysfs files if frequency table is not
cpufreq/x86: Add P-state driver for sandy bridge.

Viresh Kumar (1):
cpufreq: Don't remove sysfs link for policy->cpu

drivers/cpufreq/Kconfig.x86 | 18 +
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/cpufreq.c | 21 +-
drivers/cpufreq/cpufreq_stats.c | 5 +
drivers/cpufreq/intel_pstate.c | 829 +++++++++++++++++++++++++++++++++++++++
5 files changed, 870 insertions(+), 4 deletions(-)
create mode 100644 drivers/cpufreq/intel_pstate.c


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