If the EC GPE status is not set after checking all of the other GPEs,
acpi_s2idle_wake() returns 'false', to indicate that the SCI event
that has just triggered is not a system wakeup one, but it does that
without canceling the pending wakeup and re-arming the SCI for system
wakeup which is a mistake, because it may cause s2idle_loop() to busy
spin until the next valid wakeup event.  [If that happens, the first
spurious wakeup is still pending after acpi_s2idle_wake() has
returned, so s2idle_enter() does nothing, acpi_s2idle_wake()
is called again and it sees that the SCI has triggered, but no GPEs
are active, so 'false' is returned again, and so on.]

Fix that by moving all of the GPE checking logic from
acpi_s2idle_wake() to acpi_ec_dispatch_gpe() and making the
latter return 'true' only if a non-EC GPE has triggered and
'false' otherwise, which will cause acpi_s2idle_wake() to
cancel the pending SCI wakeup and re-arm the SCI for system
wakeup regardless of the EC GPE status.

This also addresses a lockup observed on an Elitegroup EF20EA laptop
after attempting to wake it up from suspend-to-idle by a key press.

Fixes: d5406284ff80 ("ACPI: PM: s2idle: Refine active GPEs check")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=207603
Reported-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Link: https://lore.kernel.org/linux-acpi/CAB4CAwdqo7=MvyG_PE+PGVfeA17AHF5i5JucgaKqqMX6mjArbQ@mail.gmail.com/
Reported-by: Chris Chiu <chiu@endlessm.com>
Tested-by: Chris Chiu <chiu@endlessm.com>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Pull ACPI updates from Rafael Wysocki:

   - Update the ACPICA code in the kernel to the 20200214 upstream
     release including:

       * Fix to re-enable the sleep button after wakeup (Anchal
         Agarwal).

       * Fixes for mistakes in comments and typos (Bob Moore).

       * ASL-ASL+ converter updates (Erik Kaneda).

       * Type casting cleanups (Sven Barth).

   - Clean up the intialization of the EC driver and eliminate some dead
     code from it (Rafael Wysocki).

   - Clean up the quirk tables in the AC and battery drivers (Hans de
     Goede).

   - Fix the global lock handling on x86 to ignore unspecified bit
     positions in the global lock field (Jan Engelhardt).

   - Add a new "tiny" driver for ACPI button devices exposed by VMs to
     guest kernels to send signals directly to init (Josh Triplett).

   - Add a kernel parameter to disable ACPI BGRT on x86 (Alex Hung).

   - Make the ACPI PCI host bridge and fan drivers use scnprintf() to
     avoid potential buffer overflows (Takashi Iwai).

   - Clean up assorted pieces of code:

       * Reorder "asmlinkage" to make g++ happy (Alexey Dobriyan).

       * Drop unneeded variable initialization (Colin Ian King).

       * Add missing __acquires/__releases annotations (Jules Irenge).

       * Replace list_for_each_safe() with list_for_each_entry_safe()
         (chenqiwu)"

* tag 'acpi-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (31 commits)
  ACPICA: Update version to 20200214
  ACPI: PCI: Use scnprintf() for avoiding potential buffer overflow
  ACPI: fan: Use scnprintf() for avoiding potential buffer overflow
  ACPI: EC: Eliminate EC_FLAGS_QUERY_HANDSHAKE
  ACPI: EC: Do not clear boot_ec_is_ecdt in acpi_ec_add()
  ACPI: EC: Simplify acpi_ec_ecdt_start() and acpi_ec_init()
  ACPI: EC: Consolidate event handler installation code
  acpi/x86: ignore unspecified bit positions in the ACPI global lock field
  acpi/x86: add a kernel parameter to disable ACPI BGRT
  x86/acpi: make "asmlinkage" part first thing in the function definition
  ACPI: list_for_each_safe() -> list_for_each_entry_safe()
  ACPI: video: remove redundant assignments to variable result
  ACPI: OSL: Add missing __acquires/__releases annotations
  ACPI / battery: Cleanup Lenovo Ideapad Miix 320 DMI table entry
  ACPI / AC: Cleanup DMI quirk table
  ACPI: EC: Use fast path in acpi_ec_add() for DSDT boot EC
  ACPI: EC: Simplify acpi_ec_add()
  ACPI: EC: Drop AE_NOT_FOUND special case from ec_install_handlers()
  ACPI: EC: Avoid passing redundant argument to functions
  ACPI: EC: Avoid printing confusing messages in acpi_ec_setup()
  ...

The check for any active GPEs added by commit fdde0ff8590b ("ACPI:
PM: s2idle: Prevent spurious SCIs from waking up the system") turns
out to be insufficiently precise to prevent some systems from
resuming prematurely due to a spurious EC wakeup, so refine it
by first checking if any GPEs other than the EC GPE are active
and skipping all of the SCIs coming from the EC that do not produce
any genuine wakeup events after processing.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206629
Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Reported-by: Ondřej Caletka <ondrej@caletka.cz>
Tested-by: Ondřej Caletka <ondrej@caletka.cz>
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Notice that the return value of acpi_ec_init() is discarded anyway,
so it can be void and it doesn't need to check the return values of
acpi_bus_register_driver() and acpi_ec_ecdt_start() called by it.
Thus the latter can be void too and it really has nothing to do
if acpi_ec_add() has already found an EC matching the boot one in the
namespace.  Also, acpi_ec_ecdt_get_handle() can be folded into it.

Modify the code accordingly and while at it create a propoer kerneldoc
comment to document acpi_ec_ecdt_start() and move the remark regarding
ASUS X550ZE along with the related bug URL from acpi_ec_init() into
that comment.

Additionally, fix up a stale comment in acpi_ec_init().

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

As defined in the ACPI spec section 12.11, ACPI hardware-reduced
platforms define the EC SCI interrupt as a GpioInt in the _CRS object.

This replaces the previous way of using a GPE for this interrupt;
GPE blocks are not available on reduced hardware platforms.

Add support for handling this interrupt as an EC event source, and
avoid GPE usage on reduced hardware platforms.

This enables the use of several media keys (e.g. screen brightness
up/down) on Asus UX434DA.

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

Move some routines, including acpi_ec_dispatch_gpe(), that are only
used if CONFIG_PM_SLEEP is set to the #ifdef block containing the EC
suspend and resume callbacks, to make the "full EC PM picture" easier
to follow.

While at it, move the header of acpi_ec_dispatch_gpe() in the
header file to a CONFIG_PM_SLEEP #ifdef block.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

Change acpi_ec_suspend() to use pm_suspend_no_platform() instead of
acpi_sleep_no_ec_events(), which allows the latter to be eliminated
along with the s2idle_in_progress variable which is only used by it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

The EC GPE needs to be set up for system wakeup only if there is a
driver depending on it, either intel-hid or intel-vbtn, bound to a
button device that is expected to wake up the system from sleep (such
as the power button on some Dell systems, like the XPS13 9360).  It
doesn't need to be set up for waking up the system from sleep in any
other cases and whether or not it is expected to wake up the system
from sleep doesn't depend on whether or not the LPS0 device is
present in the ACPI namespace.

For this reason, rearrange the ACPI suspend-to-idle code to make the
drivers depending on the EC GPE wakeup take care of setting it up and
decouple that from the LPS0 device handling.

While at it, make intel-hid and intel-vbtn prepare for system wakeup
only if they are allowed to wake up the system from sleep by user
space (via sysfs).

[Note that acpi_ec_mark_gpe_for_wake() and acpi_ec_set_gpe_wake_mask()
 are there to prevent the EC GPE from being disabled by the
 acpi_enable_all_wakeup_gpes() call in acpi_s2idle_prepare(), so on
 systems with either intel-hid or intel-vbtn this change doesn't
 affect any interactions with the hardware or platform firmware.]

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

On some systems, if suspend-to-idle is used, the EC may signal system
wakeup events (power button events, for example) as well as events
that should not cause the system to resume and acpi_ec_dispatch_gpe()
needs to be called to determine whether or not the system should
resume then.  In particular, if acpi_ec_dispatch_gpe() doesn't detect
any EC events at all, the system should remain suspended, so it is
useful to know when that is the case.

For this reason, make acpi_ec_dispatch_gpe() return a bool value
indicating whether or not any EC events have been detected by it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

Using acpi_device_get_power() outside of ACPI device initialization
and ACPI sysfs is problematic due to the way in which power resources
are handled by it, so unexport it and add a paragraph explaining the
pitfalls to its kerneldoc comment.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>