Commit 1a699476e258 "ACPI / hotplug / PCI: Hotplug notifications from
acpi_bus_notify()" changed the root notify handler, acpi_bus_notify(),
to block unknown type norifications, but it overlooked the fact that
they might be propagated to drivers via the ->notify() callback.

Fix the problem by allowing drivers to receive unknown type
notifications via ->notify() as before.

Fixes: 1a699476e258 (ACPI / hotplug / PCI: Hotplug notifications from acpi_bus_notify())
Reported-and-tested-by: Mantas Mikulėnas <grawity@gmail.com>
Reported-and-tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

* acpi-ost:
  ACPI: Drop acpi_evaluate_hotplug_ost() and ACPI_HOTPLUG_OST
  ACPI: use device name LNXSYBUS.xx for ACPI \_SB and \_TZ objects
  ACPI / processor: use acpi_evaluate_ost() to replace open-coded version
  ACPI / PAD / xen: use acpi_evaluate_ost() to replace open-coded version
  ACPI / PAD: use acpi_evaluate_ost() to replace open-coded version
  ACPI: rename acpi_evaluate_hotplug_ost() to acpi_evaluate_ost()

Since the only function executed by acpi_hotplug_execute() is
acpi_device_hotplug() and it only is called by the ACPI core,
simplify its definition so that it only takes two arguments, the
ACPI device object pointer and event code, rename it to
acpi_hotplug_schedule() and move its header from acpi_bus.h to
the ACPI core's internal header file internal.h.  Modify the
definition of acpi_device_hotplug() so that its first argument is
an ACPI device object pointer and modify the definition of
struct acpi_hp_work accordingly.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>

Replace acpi_evaluate_hotplug_ost() with acpi_evaluate_ost()
everywhere and drop the ACPI_HOTPLUG_OST symbol so that hotplug
_OST is supported unconditionally.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>

Since acpi_bus_notify() is executed on all notifications for all
devices anyway, make it execute acpi_device_hotplug() for all
hotplug events instead of installing notify handlers pointing to
the same function for all hotplug devices.

This change reduces both the size and complexity of ACPI-based device
hotplug code.  Moreover, since acpi_device_hotplug() only does
significant things for devices that have either an ACPI scan handler,
or a hotplug context with .eject() defined, and those devices
had notify handlers pointing to acpi_hotplug_notify_cb() installed
before anyway, this modification shouldn't change functionality.

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

There is a slight possibility for the ACPI device object pointed to
by adev in acpi_hotplug_notify_cb() to become invalid between the
acpi_bus_get_device() that it comes from and the subsequent dereference
of that pointer under get_device().  Namely, if acpi_scan_drop_device()
runs in parallel with acpi_hotplug_notify_cb(), acpi_device_del_work_fn()
queued up by it may delete the device object in question right after
a successful execution of acpi_bus_get_device() in acpi_bus_notify().

An analogous problem is present in acpi_bus_notify() where the device
pointer coming from acpi_bus_get_device() may become invalid before
it subsequent dereference in the "if" block.

To prevent that from happening, introduce a new function,
acpi_bus_get_acpi_device(), working analogously to acpi_bus_get_device()
except that it will grab a reference to the ACPI device object returned
by it and it will do that under the ACPICA's namespace mutex.  Then,
make both acpi_hotplug_notify_cb() and acpi_bus_notify() use
acpi_bus_get_acpi_device() instead of acpi_bus_get_device() so as to
ensure that the pointers used by them will not become stale at one
point.

In addition to that, introduce acpi_bus_put_acpi_device() as a wrapper
around put_device() to be used along with acpi_bus_get_acpi_device()
and make the (new) users of the latter use acpi_bus_put_acpi_device()
too.

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

* acpi-processor:
  ACPI / scan: reduce log level of "ACPI: \_PR_.CPU4: failed to get CPU APIC ID"
  ACPI / processor: Return specific error value when mapping lapic id

* acpi-hotplug:
  ACPI / scan: Clear match_driver flag in acpi_bus_trim()

* acpi-init:
  ACPI / init: Flag use of ACPI and ACPI idioms for power supplies to regulator API

* acpi-pm:
  ACPI / PM: Use ACPI_COMPANION() to get ACPI companions of devices

* acpica:
  ACPICA: Remove bool usage from ACPICA.

There is currently no facility in ACPI to express the hookup of voltage
regulators, the expectation is that the regulators that exist in the
system will be handled transparently by firmware if they need software
control at all. This means that if for some reason the regulator API is
enabled on such a system it should assume that any supplies that devices
need are provided by the system at all relevant times without any software
intervention.

Tell the regulator core to make this assumption by calling
regulator_has_full_constraints(). Do this as soon as we know we are using
ACPI so that the information is available to the regulator core as early
as possible. This will cause the regulator core to pretend that there is
an always on regulator supplying any supply that is requested but that has
not otherwise been mapped which is the behaviour expected on a system with
ACPI.

Should the ability to specify regulators be added in future revisions of
ACPI then once we have support for ACPI mappings in the kernel the same
assumptions will apply. It is also likely that systems will default to a
mode of operation which does not require any interpretation of these
mappings in order to be compatible with existing operating system releases
so it should remain safe to make these assumptions even if the mappings
exist but are not supported by the kernel.

Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Conflicts:
	include/acpi/acpi_bus.h

The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made
during the 3.12 development cycle uncovered a problem with VGA
switcheroo that on some systems, when the device-specific method
(ATPX in the radeon case, _DSM in the nouveau case) is used to turn
off the discrete graphics, the BIOS generates ACPI hotplug events for
that device and those events cause ACPIPHP to attempt to remove the
device from the system (they are events for a device that was present
previously and is not present any more, so that's what should be done
according to the spec).  Then, the system stops functioning correctly.

Since the hotplug events in question were simply silently ignored
previously, the least intrusive way to address that problem is to
make ACPIPHP ignore them again.  For this purpose, introduce a new
ACPI device flag, no_hotplug, and modify ACPIPHP to ignore hotplug
events for PCI devices whose ACPI companions have that flag set.
Next, make the radeon and nouveau switcheroo detection code set the
no_hotplug flag for the discrete graphics' ACPI companion.

Fixes: bbd34fcdd1b2 (ACPI / hotplug / PCI: Register all devices under the given bridge)
References: https://bugzilla.kernel.org/show_bug.cgi?id=61891
References: https://bugzilla.kernel.org/show_bug.cgi?id=64891
Reported-and-tested-by: Mike Lothian <mike@fireburn.co.uk>
Reported-and-tested-by: <madcatx@atlas.cz>
Reported-and-tested-by: Joaquín Aramendía <samsagax@gmail.com>
Cc: Alex Deucher <alexdeucher@gmail.com>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 3.12+ <stable@vger.kernel.org> # 3.12+