Because suspend-to-idle is always supported and on x86 it is the only
way to suspend the system if S3 is not supported by the platform, the
kernel attempts to enter low-power S0 idle in the suspend-to-idle flow
regardless of whether or not the ACPI_FADT_LOW_POWER_S0 flag is set in
the FADT.  However, if that flag is not set, residency counters
associated with low-power S0 idle may not count and the platform may
refuse to put the EC into a low-power mode, for example.

For this reason, print diagnostic messages when the platform should
achieve significant energy savings in low-power S0 idle (because the
ACPI_FADT_LOW_POWER_S0 flag is set in the FADT) and when
suspend-to-idle becomes the default suspend method (because low-power
S0 idle should be equally or more efficient than S3, if available).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>

[821d6f0359b0614792ab8e2fb93b503e25a65079] is to make machines
produced from 2012 to now not saving NVS region to accelerate S3.

But, Lenovo G40-45, a platform released in 2015, still needs NVS memory
saving during S3. A quirk is introduced for this platform.

Signed-off-by: Manyi Li <limanyi@uniontech.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Switch to sys-off API that replaces legacy pm_power_off callbacks,
allowing us to remove global pm_* variables and support chaining of
all restart and power-off modes consistently.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ASUS B1400CEAE fails to resume from suspend to idle by default.  This was
bisected back to commit df4f9bc4fb9c ("nvme-pci: add support for ACPI
StorageD3Enable property") but this is a red herring to the problem.

Before this commit the system wasn't getting into deepest sleep state.
Presumably this commit is allowing entry into deepest sleep state as
advertised by firmware, but there are some other problems related to
the wakeup.

As it is confirmed the system works properly with S3, set the default for
this system to S3.

Reported-by: Jian-Hong Pan <jhp@endlessos.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215742
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Tested-by: Jian-Hong Pan <jhp@endlessos.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull power management updates from Rafael Wysocki:
 "These are mostly fixes and cleanups all over the code and a new piece
  of documentation for Intel uncore frequency scaling.

  Functionality-wise, the intel_idle driver will support Sapphire Rapids
  Xeons natively now (with some extra facilities for controlling
  C-states more precisely on those systems), virtual guests will take
  the ACPI S4 hardware signature into account by default, the
  intel_pstate driver will take the defualt EPP value from the firmware,
  cpupower utility will support the AMD P-state driver added in the
  previous cycle, and there is a new tracer utility for that driver.

  Specifics:

   - Allow device_pm_check_callbacks() to be called from interrupt
     context without issues (Dmitry Baryshkov).

   - Modify devm_pm_runtime_enable() to automatically handle
     pm_runtime_dont_use_autosuspend() at driver exit time (Douglas
     Anderson).

   - Make the schedutil cpufreq governor use to_gov_attr_set() instead
     of open coding it (Kevin Hao).

   - Replace acpi_bus_get_device() with acpi_fetch_acpi_dev() in the
     cpufreq longhaul driver (Rafael Wysocki).

   - Unify show() and store() naming in cpufreq and make it use
     __ATTR_XX (Lianjie Zhang).

   - Make the intel_pstate driver use the EPP value set by the firmware
     by default (Srinivas Pandruvada).

   - Re-order the init checks in the powernow-k8 cpufreq driver (Mario
     Limonciello).

   - Make the ACPI processor idle driver check for architectural support
     for LPI to avoid using it on x86 by mistake (Mario Limonciello).

   - Add Sapphire Rapids Xeon support to the intel_idle driver (Artem
     Bityutskiy).

   - Add 'preferred_cstates' module argument to the intel_idle driver to
     work around C1 and C1E handling issue on Sapphire Rapids (Artem
     Bityutskiy).

   - Add core C6 optimization on Sapphire Rapids to the intel_idle
     driver (Artem Bityutskiy).

   - Optimize the haltpoll cpuidle driver a bit (Li RongQing).

   - Remove leftover text from intel_idle() kerneldoc comment and fix up
     white space in intel_idle (Rafael Wysocki).

   - Fix load_image_and_restore() error path (Ye Bin).

   - Fix typos in comments in the system wakeup hadling code (Tom Rix).

   - Clean up non-kernel-doc comments in hibernation code (Jiapeng
     Chong).

   - Fix __setup handler error handling in system-wide suspend and
     hibernation core code (Randy Dunlap).

   - Add device name to suspend_report_result() (Youngjin Jang).

   - Make virtual guests honour ACPI S4 hardware signature by default
     (David Woodhouse).

   - Block power off of a parent PM domain unless child is in deepest
     state (Ulf Hansson).

   - Use dev_err_probe() to simplify error handling for generic PM
     domains (Ahmad Fatoum).

   - Fix sleep-in-atomic bug caused by genpd_debug_remove() (Shawn Guo).

   - Document Intel uncore frequency scaling (Srinivas Pandruvada).

   - Add DTPM hierarchy description (Daniel Lezcano).

   - Change the locking scheme in DTPM (Daniel Lezcano).

   - Fix dtpm_cpu cleanup at exit time and missing virtual DTPM pointer
     release (Daniel Lezcano).

   - Make dtpm_node_callback[] static (kernel test robot).

   - Fix spelling mistake "initialze" -> "initialize" in
     dtpm_create_hierarchy() (Colin Ian King).

   - Add tracer tool for the amd-pstate driver (Jinzhou Su).

   - Fix PC6 displaying in turbostat on some systems (Artem Bityutskiy).

   - Add AMD P-State support to the cpupower utility (Huang Rui)"

* tag 'pm-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (58 commits)
  cpufreq: powernow-k8: Re-order the init checks
  cpuidle: intel_idle: Drop redundant backslash at line end
  cpuidle: intel_idle: Update intel_idle() kerneldoc comment
  PM: hibernate: Honour ACPI hardware signature by default for virtual guests
  cpufreq: intel_pstate: Use firmware default EPP
  cpufreq: unify show() and store() naming and use __ATTR_XX
  PM: core: keep irq flags in device_pm_check_callbacks()
  cpuidle: haltpoll: Call cpuidle_poll_state_init() later
  Documentation: amd-pstate: add tracer tool introduction
  tools/power/x86/amd_pstate_tracer: Add tracer tool for AMD P-state
  tools/power/x86/intel_pstate_tracer: make tracer as a module
  cpufreq: amd-pstate: Add more tracepoint for AMD P-State module
  PM: sleep: Add device name to suspend_report_result()
  turbostat: fix PC6 displaying on some systems
  intel_idle: add core C6 optimization for SPR
  intel_idle: add 'preferred_cstates' module argument
  intel_idle: add SPR support
  PM: runtime: Have devm_pm_runtime_enable() handle pm_runtime_dont_use_autosuspend()
  ACPI: processor idle: Check for architectural support for LPI
  cpuidle: PSCI: Move the `has_lpi` check to the beginning of the function
  ...

The ACPI specification says that OSPM should refuse to restore from
hibernate if the hardware signature changes, and should boot from
scratch. However, real BIOSes often vary the hardware signature in cases
where we *do* want to resume from hibernate, so Linux doesn't follow the
spec by default.

However, in a virtual environment there's no reason for the VMM to vary
the hardware signature *unless* it wants to trigger a clean reboot as
defined by the ACPI spec. So enable the check by default if a hypervisor
is detected.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Make acpi_s2idle_wake() print an additional debug message when the
SCI is going to be rearmed for system wakeup to help diagnose
wakeup-related issues.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

After commit e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race
related to the EC GPE") wakeup interrupts occurring immediately after
the one discarded by acpi_s2idle_wake() may be missed.  Moreover, if
the SCI triggers again immediately after the rearming in
acpi_s2idle_wake(), that wakeup may be missed too.

The problem is that pm_system_irq_wakeup() only calls pm_system_wakeup()
when pm_wakeup_irq is 0, but that's not the case any more after the
interrupt causing acpi_s2idle_wake() to run until pm_wakeup_irq is
cleared by the pm_wakeup_clear() call in s2idle_loop().  However,
there may be wakeup interrupts occurring in that time frame and if
that happens, they will be missed.

To address that issue first move the clearing of pm_wakeup_irq to
the point at which it is known that the interrupt causing
acpi_s2idle_wake() to tun will be discarded, before rearming the SCI
for wakeup.  Moreover, because that only reduces the size of the
time window in which the issue may manifest itself, allow
pm_system_irq_wakeup() to register two second wakeup interrupts in
a row and, when discarding the first one, replace it with the second
one.  [Of course, this assumes that only one wakeup interrupt can be
discarded in one go, but currently that is the case and I am not
aware of any plans to change that.]

Fixes: e3728b50cd9b ("ACPI: PM: s2idle: Avoid possible race related to the EC GPE")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Commit 4a9af6cac050 ("ACPI: EC: Rework flushing of EC work while
suspended to idle") made acpi_ec_dispatch_gpe() check
pm_wakeup_pending(), but that is before canceling the SCI wakeup,
so pm_wakeup_pending() is always true.  This causes the loop in
acpi_ec_dispatch_gpe() to always terminate after one iteration which
may not be correct.

Address this issue by canceling the SCI wakeup earlier, from
acpi_ec_dispatch_gpe() itself.

Fixes: 4a9af6cac050 ("ACPI: EC: Rework flushing of EC work while suspended to idle")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>