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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-02-20 16:23:00 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-02-20 16:23:00 +0300
commitf6cbe34f52dedd67d156b3d5dd76eb43791ea34a (patch)
treecc0dc22e85624ddc632b3fef69ef1a18d17e4805 /Documentation/cpu-freq/intel-pstate.txt
parent64f758a07a8cdb5c2a08e0d3dfec323af1d2bac3 (diff)
parent20bb5505e96f00a997fa78cf60d6d9156b19d435 (diff)
downloadlinux-f6cbe34f52dedd67d156b3d5dd76eb43791ea34a.tar.xz
Merge branch 'pm-cpufreq'
* pm-cpufreq: (28 commits) MAINTAINERS: cpufreq: add bmips-cpufreq.c cpufreq: CPPC: add ACPI_PROCESSOR dependency cpufreq: make ti-cpufreq explicitly non-modular cpufreq: Do not clear real_cpus mask on policy init cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms cpufreq: ti: Add cpufreq driver to determine available OPPs at runtime Documentation: dt: add bindings for ti-cpufreq cpufreq: qoriq: Don't look at clock implementation details cpufreq: qoriq: add ARM64 SoCs support cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata() cpufreq: s3c2416: double free on driver init error path MIPS: BMIPS: enable CPUfreq cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs BMIPS: Enable prerequisites for CPUfreq in MIPS Kconfig. MIPS: BMIPS: Update defconfig cpufreq: Fix typos in comments cpufreq: intel_pstate: Calculate guaranteed performance for HWP cpufreq: intel_pstate: Make HWP limits compatible with legacy cpufreq: intel_pstate: Lower frequency than expected under no_turbo cpufreq: intel_pstate: Operation mode control from sysfs ...
Diffstat (limited to 'Documentation/cpu-freq/intel-pstate.txt')
-rw-r--r--Documentation/cpu-freq/intel-pstate.txt15
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/cpu-freq/intel-pstate.txt b/Documentation/cpu-freq/intel-pstate.txt
index 1953994ef5e6..3fdcdfd968ba 100644
--- a/Documentation/cpu-freq/intel-pstate.txt
+++ b/Documentation/cpu-freq/intel-pstate.txt
@@ -85,6 +85,21 @@ Sysfs will show :
Refer to "Intel® 64 and IA-32 Architectures Software Developer’s Manual
Volume 3: System Programming Guide" to understand ratios.
+There is one more sysfs attribute in /sys/devices/system/cpu/intel_pstate/
+that can be used for controlling the operation mode of the driver:
+
+ status: Three settings are possible:
+ "off" - The driver is not in use at this time.
+ "active" - The driver works as a P-state governor (default).
+ "passive" - The driver works as a regular cpufreq one and collaborates
+ with the generic cpufreq governors (it sets P-states as
+ requested by those governors).
+ The current setting is returned by reads from this attribute. Writing one
+ of the above strings to it changes the operation mode as indicated by that
+ string, if possible. If HW-managed P-states (HWP) are enabled, it is not
+ possible to change the driver's operation mode and attempts to write to
+ this attribute will fail.
+
cpufreq sysfs for Intel P-State
Since this driver registers with cpufreq, cpufreq sysfs is also presented.