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
/sys/devices/system/cpu/intel_pstate/
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
processor
Changes since last version:
Dropped unneeded patches.
Rebased on bleeding edge 1071b3b
Patch 1:
updated per Viresh's comments, added his ack.
Patch 2:
updated description to be more informative and move the check as
to whether the scaling driver implements target() to only effect
whether cpufreq_out_of_sync() is called
Patch 3:
Added Viresh's Ack
Patch 4:
Upadted to not use unneeded local variable
Dirk Brandewie (5):
cpufreq: Retrieve current frequency from scaling drivers with
internal governors
cpufreq: Only call cpufreq_out_of_sync() with drivers that implement
cpufreq_driver.target()
cpufreq: Do not track governor name for scaling drivers with internal
governors.
cpufreq_stats: do not remove sysfs files if frequency table is not
present
cpufreq/x86: Add P-state driver for sandy bridge.
drivers/cpufreq/Kconfig.x86 | 18 +
drivers/cpufreq/Makefile | 1 +
drivers/cpufreq/cpufreq.c | 13 +-
drivers/cpufreq/cpufreq_stats.c | 4 +
drivers/cpufreq/intel_pstate.c | 829 +++++++++++++++++++++++++++++++++++++++
5 files changed, 862 insertions(+), 3 deletions(-)
create mode 100644 drivers/cpufreq/intel_pstate.c
--
1.7.7.6
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