Merge tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "This includes some infrastructure changes in the PM core, mostly
  related to integration between runtime PM and system-wide suspend and
  hibernation, plus some driver changes depending on them and fixes for
  issues in that area which have become quite apparent recently.

  Also included are changes making more x86-based systems use the Low
  Power Sleep S0 _DSM interface by default, which turned out to be
  necessary to handle power button wakeups from suspend-to-idle on
  Surface Pro3.

  On the cpufreq front we have fixes and cleanups in the core, some new
  hardware support, driver updates and the removal of some unused code
  from the CPU cooling thermal driver.

  Apart from this, the Operating Performance Points (OPP) framework is
  prepared to be used with power domains in the future and there is a
  usual bunch of assorted fixes and cleanups.

  Specifics:

   - Define a PM driver flag allowing drivers to request that their
     devices be left in suspend after system-wide transitions to the
     working state if possible and add support for it to the PCI bus
     type and the ACPI PM domain (Rafael Wysocki).

   - Make the PM core carry out optimizations for devices with driver PM
     flags set in some cases and make a few drivers set those flags
     (Rafael Wysocki).

   - Fix and clean up wrapper routines allowing runtime PM device
     callbacks to be re-used for system-wide PM, change the generic
     power domains (genpd) framework to stop using those routines
     incorrectly and fix up a driver depending on that behavior of genpd
     (Rafael Wysocki, Ulf Hansson, Geert Uytterhoeven).

   - Fix and clean up the PM core's device wakeup framework and
     re-factor system-wide PM core code related to device wakeup
     (Rafael Wysocki, Ulf Hansson, Brian Norris).

   - Make more x86-based systems use the Low Power Sleep S0 _DSM
     interface by default (to fix power button wakeup from
     suspend-to-idle on Surface Pro3) and add a kernel command line
     switch to tell it to ignore the system sleep blacklist in the ACPI
     core (Rafael Wysocki).

   - Fix a race condition related to cpufreq governor module removal and
     clean up the governor management code in the cpufreq core (Rafael
     Wysocki).

   - Drop the unused generic code related to the handling of the static
     power energy usage model in the CPU cooling thermal driver along
     with the corresponding documentation (Viresh Kumar).

   - Add mt2712 support to the Mediatek cpufreq driver (Andrew-sh
     Cheng).

   - Add a new operating point to the imx6ul and imx6q cpufreq drivers
     and switch the latter to using clk_bulk_get() (Anson Huang, Dong
     Aisheng).

   - Add support for multiple regulators to the TI cpufreq driver along
     with a new DT binding related to that and clean up that driver
     somewhat (Dave Gerlach).

   - Fix a powernv cpufreq driver regression leading to incorrect CPU
     frequency reporting, fix that driver to deal with non-continguous
     P-states correctly and clean it up (Gautham Shenoy, Shilpasri
     Bhat).

   - Add support for frequency scaling on Armada 37xx SoCs through the
     generic DT cpufreq driver (Gregory CLEMENT).

   - Fix error code paths in the mvebu cpufreq driver (Gregory CLEMENT).

   - Fix a transition delay setting regression in the longhaul cpufreq
     driver (Viresh Kumar).

   - Add Skylake X (server) support to the intel_pstate cpufreq driver
     and clean up that driver somewhat (Srinivas Pandruvada).

   - Clean up the cpufreq statistics collection code (Viresh Kumar).

   - Drop cluster terminology and dependency on physical_package_id from
     the PSCI driver and drop dependency on arm_big_little from the SCPI
     cpufreq driver (Sudeep Holla).

   - Add support for system-wide suspend and resume to the RAPL power
     capping driver and drop a redundant semicolon from it (Zhen Han,
     Luis de Bethencourt).

   - Make SPI domain validation (in the SCSI SPI transport driver) and
     system-wide suspend mutually exclusive as they rely on the same
     underlying mechanism and cannot be carried out at the same time
     (Bart Van Assche).

   - Fix the computation of the amount of memory to preallocate in the
     hibernation core and clean up one function in there (Rainer Fiebig,
     Kyungsik Lee).

   - Prepare the Operating Performance Points (OPP) framework for being
     used with power domains and clean up one function in it (Viresh
     Kumar, Wei Yongjun).

   - Clean up the generic sysfs interface for device PM (Andy
     Shevchenko).

   - Fix several minor issues in power management frameworks and clean
     them up a bit (Arvind Yadav, Bjorn Andersson, Geert Uytterhoeven,
     Gustavo Silva, Julia Lawall, Luis de Bethencourt, Paul Gortmaker,
     Sergey Senozhatsky, gaurav jindal).

   - Make it easier to disable PM via Kconfig (Mark Brown).

   - Clean up the cpupower and intel_pstate_tracer utilities (Doug
     Smythies, Laura Abbott)"

* tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
  PCI / PM: Remove spurious semicolon
  cpufreq: scpi: remove arm_big_little dependency
  drivers: psci: remove cluster terminology and dependency on physical_package_id
  powercap: intel_rapl: Fix trailing semicolon
  dmaengine: rcar-dmac: Make DMAC reinit during system resume explicit
  PM / runtime: Allow no callbacks in pm_runtime_force_suspend|resume()
  PM / hibernate: Drop unused parameter of enough_swap
  PM / runtime: Check ignore_children in pm_runtime_need_not_resume()
  PM / runtime: Rework pm_runtime_force_suspend/resume()
  PM / genpd: Stop/start devices without pm_runtime_force_suspend/resume()
  cpufreq: powernv: Dont assume distinct pstate values for nominal and pmin
  cpufreq: intel_pstate: Add Skylake servers support
  cpufreq: intel_pstate: Replace bxt_funcs with core_funcs
  platform/x86: surfacepro3: Support for wakeup from suspend-to-idle
  ACPI / PM: Use Low Power S0 Idle on more systems
  PM / wakeup: Print warn if device gets enabled as wakeup source during sleep
  PM / domains: Don't skip driver's ->suspend|resume_noirq() callbacks
  PM / core: Propagate wakeup_path status flag in __device_suspend_late()
  PM / core: Re-structure code for clearing the direct_complete flag
  powercap: add suspend and resume mechanism for SOC power limit
  ...

1 files changed, 44 insertions, 10 deletions

diff --git a/Documentation/driver-api/pm/devices.rst b/Documentation/driver-api/pm/devices.rst
index 53c1b0b06da5..1128705a5731 100644
--- a/Documentation/driver-api/pm/devices.rst
+++ b/Documentation/driver-api/pm/devices.rst
@@ -777,17 +777,51 @@ The driver can indicate that by setting ``DPM_FLAG_SMART_SUSPEND`` in
 runtime suspend at the beginning of the ``suspend_late`` phase of system-wide
 suspend (or in the ``poweroff_late`` phase of hibernation), when runtime PM
 has been disabled for it, under the assumption that its state should not change
-after that point until the system-wide transition is over.  If that happens, the
-driver's system-wide resume callbacks, if present, may still be invoked during
-the subsequent system-wide resume transition and the device's runtime power
-management status may be set to "active" before enabling runtime PM for it,
-so the driver must be prepared to cope with the invocation of its system-wide
-resume callbacks back-to-back with its ``->runtime_suspend`` one (without the
-intervening ``->runtime_resume`` and so on) and the final state of the device
-must reflect the "active" status for runtime PM in that case.
+after that point until the system-wide transition is over (the PM core itself
+does that for devices whose "noirq", "late" and "early" system-wide PM callbacks
+are executed directly by it).  If that happens, the driver's system-wide resume
+callbacks, if present, may still be invoked during the subsequent system-wide
+resume transition and the device's runtime power management status may be set
+to "active" before enabling runtime PM for it, so the driver must be prepared to
+cope with the invocation of its system-wide resume callbacks back-to-back with
+its ``->runtime_suspend`` one (without the intervening ``->runtime_resume`` and
+so on) and the final state of the device must reflect the "active" runtime PM
+status in that case.
 
 During system-wide resume from a sleep state it's easiest to put devices into
 the full-power state, as explained in :file:`Documentation/power/runtime_pm.txt`.
-Refer to that document for more information regarding this particular issue as
+[Refer to that document for more information regarding this particular issue as
 well as for information on the device runtime power management framework in
-general.
+general.]
+
+However, it often is desirable to leave devices in suspend after system
+transitions to the working state, especially if those devices had been in
+runtime suspend before the preceding system-wide suspend (or analogous)
+transition.  Device drivers can use the ``DPM_FLAG_LEAVE_SUSPENDED`` flag to
+indicate to the PM core (and middle-layer code) that they prefer the specific
+devices handled by them to be left suspended and they have no problems with
+skipping their system-wide resume callbacks for this reason.  Whether or not the
+devices will actually be left in suspend may depend on their state before the
+given system suspend-resume cycle and on the type of the system transition under
+way.  In particular, devices are not left suspended if that transition is a
+restore from hibernation, as device states are not guaranteed to be reflected
+by the information stored in the hibernation image in that case.
+
+The middle-layer code involved in the handling of the device is expected to
+indicate to the PM core if the device may be left in suspend by setting its
+:c:member:`power.may_skip_resume` status bit which is checked by the PM core
+during the "noirq" phase of the preceding system-wide suspend (or analogous)
+transition.  The middle layer is then responsible for handling the device as
+appropriate in its "noirq" resume callback, which is executed regardless of
+whether or not the device is left suspended, but the other resume callbacks
+(except for ``->complete``) will be skipped automatically by the PM core if the
+device really can be left in suspend.
+
+For devices whose "noirq", "late" and "early" driver callbacks are invoked
+directly by the PM core, all of the system-wide resume callbacks are skipped if
+``DPM_FLAG_LEAVE_SUSPENDED`` is set and the device is in runtime suspend during
+the ``suspend_noirq`` (or analogous) phase or the transition under way is a
+proper system suspend (rather than anything related to hibernation) and the
+device's wakeup settings are suitable for runtime PM (that is, it cannot
+generate wakeup signals at all or it is allowed to wake up the system from
+sleep).