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Commit 801099be authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'pm-4.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm 

Pull power management fixes from Rafael Wysocki:
 "These fix RTC wakeup from suspend-to-idle broken recently, fix CPU
  idleness detection condition in the schedutil cpufreq governor, fix a
  cpufreq driver build failure, fix an error code path in the power
  capping framework, clean up the hibernate core and update the
  intel_pstate documentation.

  Specifics:

   - Fix RTC wakeup from suspend-to-idle broken by the recent rework of
     ACPI wakeup handling (Rafael Wysocki).

   - Update intel_pstate driver documentation to reflect the current
     code and explain how it works in more detail (Rafael Wysocki).

   - Fix an issue related to CPU idleness detection on systems with
     shared cpufreq policies in the schedutil governor (Juri Lelli).

   - Fix a possible build issue in the dbx500 cpufreq driver (Arnd
     Bergmann).

   - Fix a function in the power capping framework core to return an
     error code instead of 0 when there's an error (Dan Carpenter).

   - Clean up variable definition in the hibernation core (Pushkar
     Jambhlekar)"

* tag 'pm-4.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  cpufreq: dbx500: add a Kconfig symbol
  PM / hibernate: Declare variables as static
  PowerCap: Fix an error code in powercap_register_zone()
  RTC: rtc-cmos: Fix wakeup from suspend-to-idle
  PM / wakeup: Fix up wakeup_source_report_event()
  cpufreq: intel_pstate: Document the current behavior and user interface
  cpufreq: schedutil: use now as reference when aggregating shared policy requests
parents ad258fb9 bb47e964

Documentation/admin-guide/pm/cpufreq.rst

+10 −9
Original line number Diff line number Diff line 
.. |struct cpufreq_policy| replace:: :c:type:`struct cpufreq_policy <cpufreq_policy>`

.. |intel_pstate| replace:: :doc:`intel_pstate <intel_pstate>`



=======================

CPU Performance Scaling
@@ -75,7 +76,7 @@ feedback registers, as that information is typically specific to the hardware 
interface it comes from and may not be easily represented in an abstract,

platform-independent way.  For this reason, ``CPUFreq`` allows scaling drivers

to bypass the governor layer and implement their own performance scaling

algorithms.  That is done by the ``intel_pstate`` scaling driver.

algorithms.  That is done by the |intel_pstate| scaling driver.





``CPUFreq`` Policy Objects
@@ -174,13 +175,13 @@ necessary to restart the scaling governor so that it can take the new online CPU 
into account.  That is achieved by invoking the governor's ``->stop`` and

``->start()`` callbacks, in this order, for the entire policy.



As mentioned before, the ``intel_pstate`` scaling driver bypasses the scaling

As mentioned before, the |intel_pstate| scaling driver bypasses the scaling

governor layer of ``CPUFreq`` and provides its own P-state selection algorithms.

Consequently, if ``intel_pstate`` is used, scaling governors are not attached to

Consequently, if |intel_pstate| is used, scaling governors are not attached to

new policy objects.  Instead, the driver's ``->setpolicy()`` callback is invoked

to register per-CPU utilization update callbacks for each policy.  These

callbacks are invoked by the CPU scheduler in the same way as for scaling

governors, but in the ``intel_pstate`` case they both determine the P-state to

governors, but in the |intel_pstate| case they both determine the P-state to

use and change the hardware configuration accordingly in one go from scheduler

context.
@@ -257,7 +258,7 @@ are the following: 


``scaling_available_governors``

	List of ``CPUFreq`` scaling governors present in the kernel that can

	be attached to this policy or (if the ``intel_pstate`` scaling driver is

	be attached to this policy or (if the |intel_pstate| scaling driver is

	in use) list of scaling algorithms provided by the driver that can be

	applied to this policy.
@@ -274,7 +275,7 @@ are the following: 
	the CPU is actually running at (due to hardware design and other

	limitations).



	Some scaling drivers (e.g. ``intel_pstate``) attempt to provide

	Some scaling drivers (e.g. |intel_pstate|) attempt to provide

	information more precisely reflecting the current CPU frequency through

	this attribute, but that still may not be the exact current CPU

	frequency as seen by the hardware at the moment.
@@ -284,13 +285,13 @@ are the following: 


``scaling_governor``

	The scaling governor currently attached to this policy or (if the

	``intel_pstate`` scaling driver is in use) the scaling algorithm

	|intel_pstate| scaling driver is in use) the scaling algorithm

	provided by the driver that is currently applied to this policy.



	This attribute is read-write and writing to it will cause a new scaling

	governor to be attached to this policy or a new scaling algorithm

	provided by the scaling driver to be applied to it (in the

	``intel_pstate`` case), as indicated by the string written to this

	|intel_pstate| case), as indicated by the string written to this

	attribute (which must be one of the names listed by the

	``scaling_available_governors`` attribute described above).
@@ -619,7 +620,7 @@ This file is located under :file:`/sys/devices/system/cpu/cpufreq/` and controls 
the "boost" setting for the whole system.  It is not present if the underlying

scaling driver does not support the frequency boost mechanism (or supports it,

but provides a driver-specific interface for controlling it, like

``intel_pstate``).

|intel_pstate|).



If the value in this file is 1, the frequency boost mechanism is enabled.  This

means that either the hardware can be put into states in which it is able to

Documentation/admin-guide/pm/index.rst

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ Power Management 
   :maxdepth: 2



   cpufreq

   intel_pstate



.. only::  subproject and html