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authorLinus Torvalds <torvalds@linux-foundation.org>2017-07-04 13:39:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-04 13:39:41 -0700
commit408c9861c6979db974455b9e7a9bcadd60e0934c (patch)
tree9bdb862da2883cd4f74297d01ec8ce3b4619dd66 /Documentation/admin-guide
parentb39de277b02ffd8e3dccb01e9159bd45cb07b95d (diff)
parent8f8e5c3e2796eaf150d6262115af12707c2616dd (diff)
Merge tag 'pm-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki: "The big ticket items here are the rework of suspend-to-idle in order to add proper support for power button wakeup from it on recent Dell laptops and the rework of interfaces exporting the current CPU frequency on x86. In addition to that, support for a few new pieces of hardware is added, the PCI/ACPI device wakeup infrastructure is simplified significantly and the wakeup IRQ framework is fixed to unbreak the IRQ bus locking infrastructure. Also, there are some functional improvements for intel_pstate, tools updates and small fixes and cleanups all over. Specifics: - Rework suspend-to-idle to allow it to take wakeup events signaled by the EC into account on ACPI-based platforms in order to properly support power button wakeup from suspend-to-idle on recent Dell laptops (Rafael Wysocki). That includes the core suspend-to-idle code rework, support for the Low Power S0 _DSM interface, and support for the ACPI INT0002 Virtual GPIO device from Hans de Goede (required for USB keyboard wakeup from suspend-to-idle to work on some machines). - Stop trying to export the current CPU frequency via /proc/cpuinfo on x86 as that is inaccurate and confusing (Len Brown). - Rework the way in which the current CPU frequency is exported by the kernel (over the cpufreq sysfs interface) on x86 systems with the APERF and MPERF registers by always using values read from these registers, when available, to compute the current frequency regardless of which cpufreq driver is in use (Len Brown). - Rework the PCI/ACPI device wakeup infrastructure to remove the questionable and artificial distinction between "devices that can wake up the system from sleep states" and "devices that can generate wakeup signals in the working state" from it, which allows the code to be simplified quite a bit (Rafael Wysocki). - Fix the wakeup IRQ framework by making it use SRCU instead of RCU which doesn't allow sleeping in the read-side critical sections, but which in turn is expected to be allowed by the IRQ bus locking infrastructure (Thomas Gleixner). - Modify some computations in the intel_pstate driver to avoid rounding errors resulting from them (Srinivas Pandruvada). - Reduce the overhead of the intel_pstate driver in the HWP (hardware-managed P-states) mode and when the "performance" P-state selection algorithm is in use by making it avoid registering scheduler callbacks in those cases (Len Brown). - Rework the energy_performance_preference sysfs knob in intel_pstate by changing the values that correspond to different symbolic hint names used by it (Len Brown). - Make it possible to use more than one cpuidle driver at the same time on ARM (Daniel Lezcano). - Make it possible to prevent the cpuidle menu governor from using the 0 state by disabling it via sysfs (Nicholas Piggin). - Add support for FFH (Fixed Functional Hardware) MWAIT in ACPI C1 on AMD systems (Yazen Ghannam). - Make the CPPC cpufreq driver take the lowest nonlinear performance information into account (Prashanth Prakash). - Add support for hi3660 to the cpufreq-dt driver, fix the imx6q driver and clean up the sfi, exynos5440 and intel_pstate drivers (Colin Ian King, Krzysztof Kozlowski, Octavian Purdila, Rafael Wysocki, Tao Wang). - Fix a few minor issues in the generic power domains (genpd) framework and clean it up somewhat (Krzysztof Kozlowski, Mikko Perttunen, Viresh Kumar). - Fix a couple of minor issues in the operating performance points (OPP) framework and clean it up somewhat (Viresh Kumar). - Fix a CONFIG dependency in the hibernation core and clean it up slightly (Balbir Singh, Arvind Yadav, BaoJun Luo). - Add rk3228 support to the rockchip-io adaptive voltage scaling (AVS) driver (David Wu). - Fix an incorrect bit shift operation in the RAPL power capping driver (Adam Lessnau). - Add support for the EPP field in the HWP (hardware managed P-states) control register, HWP.EPP, to the x86_energy_perf_policy tool and update msr-index.h with HWP.EPP values (Len Brown). - Fix some minor issues in the turbostat tool (Len Brown). - Add support for AMD family 0x17 CPUs to the cpupower tool and fix a minor issue in it (Sherry Hurwitz). - Assorted cleanups, mostly related to the constification of some data structures (Arvind Yadav, Joe Perches, Kees Cook, Krzysztof Kozlowski)" * tag 'pm-4.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (69 commits) cpufreq: Update scaling_cur_freq documentation cpufreq: intel_pstate: Clean up after performance governor changes PM: hibernate: constify attribute_group structures. cpuidle: menu: allow state 0 to be disabled intel_idle: Use more common logging style PM / Domains: Fix missing default_power_down_ok comment PM / Domains: Fix unsafe iteration over modified list of domains PM / Domains: Fix unsafe iteration over modified list of domain providers PM / Domains: Fix unsafe iteration over modified list of device links PM / Domains: Handle safely genpd_syscore_switch() call on non-genpd device PM / Domains: Call driver's noirq callbacks PM / core: Drop run_wake flag from struct dev_pm_info PCI / PM: Simplify device wakeup settings code PCI / PM: Drop pme_interrupt flag from struct pci_dev ACPI / PM: Consolidate device wakeup settings code ACPI / PM: Drop run_wake from struct acpi_device_wakeup_flags PM / QoS: constify *_attribute_group. PM / AVS: rockchip-io: add io selectors and supplies for rk3228 powercap/RAPL: prevent overridding bits outside of the mask PM / sysfs: Constify attribute groups ...
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/pm/cpufreq.rst12
-rw-r--r--Documentation/admin-guide/pm/intel_pstate.rst6
2 files changed, 8 insertions, 10 deletions
diff --git a/Documentation/admin-guide/pm/cpufreq.rst b/Documentation/admin-guide/pm/cpufreq.rst
index 09aa2e949787..463cf7e73db8 100644
--- a/Documentation/admin-guide/pm/cpufreq.rst
+++ b/Documentation/admin-guide/pm/cpufreq.rst
@@ -269,16 +269,16 @@ are the following:
``scaling_cur_freq``
Current frequency of all of the CPUs belonging to this policy (in kHz).
- For the majority of scaling drivers, this is the frequency of the last
- P-state requested by the driver from the hardware using the scaling
+ In the majority of cases, this is the frequency of the last P-state
+ requested by the scaling driver from the hardware using the scaling
interface provided by it, which may or may not reflect the frequency
the CPU is actually running at (due to hardware design and other
limitations).
- 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.
+ Some architectures (e.g. ``x86``) may 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.
``scaling_driver``
The scaling driver currently in use.
diff --git a/Documentation/admin-guide/pm/intel_pstate.rst b/Documentation/admin-guide/pm/intel_pstate.rst
index 33d703989ea8..1d6249825efc 100644
--- a/Documentation/admin-guide/pm/intel_pstate.rst
+++ b/Documentation/admin-guide/pm/intel_pstate.rst
@@ -157,10 +157,8 @@ Without HWP, this P-state selection algorithm is always the same regardless of
the processor model and platform configuration.
It selects the maximum P-state it is allowed to use, subject to limits set via
-``sysfs``, every time the P-state selection computations are carried out by the
-driver's utilization update callback for the given CPU (that does not happen
-more often than every 10 ms), but the hardware configuration will not be changed
-if the new P-state is the same as the current one.
+``sysfs``, every time the driver configuration for the given CPU is updated
+(e.g. via ``sysfs``).
This is the default P-state selection algorithm if the
:c:macro:`CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE` kernel configuration option