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Hans de Goede ddfd9dcf27 ACPI: PM: Add acpi_[un]register_wakeup_handler()
Since commit fdde0ff859 ("ACPI: PM: s2idle: Prevent spurious SCIs from
waking up the system") the SCI triggering without there being a wakeup
cause recognized by the ACPI sleep code will no longer wakeup the system.

This works as intended, but this is a problem for devices where the SCI
is shared with another device which is also a wakeup source.

In the past these, from the pov of the ACPI sleep code, spurious SCIs
would still cause a wakeup so the wakeup from the device sharing the
interrupt would actually wakeup the system. This now no longer works.

This is a problem on e.g. Bay Trail-T and Cherry Trail devices where
some peripherals (typically the XHCI controller) can signal a
Power Management Event (PME) to the Power Management Controller (PMC)
to wakeup the system, this uses the same interrupt as the SCI.
These wakeups are handled through a special INT0002 ACPI device which
checks for events in the GPE0a_STS for this and takes care of acking
the PME so that the shared interrupt stops triggering.

The change to the ACPI sleep code to ignore the spurious SCI, causes
the system to no longer wakeup on these PME events. To make things
worse this means that the INT0002 device driver interrupt handler will
no longer run, causing the PME to not get cleared and resulting in the
system hanging. Trying to wakeup the system after such a PME through e.g.
the power button no longer works.

Add an acpi_register_wakeup_handler() function which registers
a handler to be called from acpi_s2idle_wake() and when the handler
returns true, return true from acpi_s2idle_wake().

The INT0002 driver will use this mechanism to check the GPE0a_STS
register from acpi_s2idle_wake() and to tell the system to wakeup
if a PME is signaled in the register.

Fixes: fdde0ff859 ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system")
Cc: 5.4+ <stable@vger.kernel.org> # 5.4+
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-04-04 19:45:18 +02:00
arch ACPI updates for 5.7-rc1 2020-03-30 15:17:04 -07:00
block for-5.7/drivers-2020-03-29 2020-03-30 11:43:51 -07:00
certs certs: Add wrapper function to check blacklisted binary hash 2019-11-12 12:25:50 +11:00
crypto Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity 2020-02-20 15:15:16 -08:00
Documentation ACPI updates for 5.7-rc1 2020-03-30 15:17:04 -07:00
drivers ACPI: PM: Add acpi_[un]register_wakeup_handler() 2020-04-04 19:45:18 +02:00
fs Driver core patches for 5.7-rc1 2020-03-30 13:59:52 -07:00
include ACPI: PM: Add acpi_[un]register_wakeup_handler() 2020-04-04 19:45:18 +02:00
init for-5.7/block-2020-03-29 2020-03-30 11:20:13 -07:00
ipc Revert "ipc,sem: remove uneeded sem_undo_list lock usage in exit_sem()" 2020-02-21 11:22:15 -08:00
kernel Power management updates for 5.7-rc1 2020-03-30 15:05:01 -07:00
lib Driver core patches for 5.7-rc1 2020-03-30 13:59:52 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/sparse: fix kernel crash with pfn_section_valid check 2020-03-29 09:47:06 -07:00
net This has been a busy cycle for documentation work. Highlights include: 2020-03-30 12:45:23 -07:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2020-02-24 16:52:39 +01:00
scripts This has been a busy cycle for documentation work. Highlights include: 2020-03-30 12:45:23 -07:00
security KEYS: reaching the keys quotas correctly 2020-03-15 20:59:50 +02:00
sound Merge branch 'pm-qos' 2020-03-30 14:45:57 +02:00
tools Power management updates for 5.7-rc1 2020-03-30 15:05:01 -07:00
usr initramfs: restore default compression behavior 2020-03-17 09:50:37 +09:00
virt KVM/arm fixes for 5.6, take #1 2020-02-28 11:50:06 +01:00
.clang-format clang-format: Update with the latest for_each macro list 2020-03-06 21:50:05 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore selftest/lkdtm: Use local .gitignore 2020-03-02 08:39:39 -07:00
.mailmap media updates for v5.7-rc1 2020-03-30 13:42:05 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Hand MIPS over to Thomas 2020-02-24 22:43:18 -08:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS PNP subsystem updates for 5.7-rc1 2020-03-30 15:28:12 -07:00
Makefile Linux 5.6 2020-03-29 15:25:41 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.