It certainly is not a good idea to execute _ON or _OFF and _STA
for the same power resource at the same time which may happen in
some circumstances in theory.  To prevent that from happening,
read the power state of each power resource under its mutex, as
that will prevent the state from being changed at the same time.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

Rename acpi_power_off_device() to acpi_power_off() in analogy with
acpi_power_on().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

Since acpi_bus_set_power() should not use __acpi_bus_get_power() to
update the device's device->power.state field before changing its
power state (this may cause device->power.state to be inconsistent
with the device power resources' reference counters), remove this
call from it.  In consequence, the acpi_power_nocheck variable is not
necessary any more, so it can be dropped along with the DMI table
used for setting that variable for HP Pavilion 05.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

Introduce function acpi_power_on_resources() that reference counts
and possibly turns on ACPI power resources for a given device and
a given power state of it.

This function will be used for reference counting device power
resources during initialization.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

ACPI device power resources should be reference counted during
device initialization, so that their reference counters are always
up to date.  It is convenient to do that with the help of a function
that will reference count and possibly turn on power resources in
a given list, so introduce that function, acpi_power_on_list().
For symmetry, introduce acpi_power_off_list() for performing the
reverse operation and use the both of them to simplify
acpi_power_transition().

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

acpi_power_get_inferred_state() should not update
device->power.state behind the back of its caller, so make it return
the state via a pointer instead.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

If turning on a power resource fails, do not reference count it,
since it cannot be in use in that case.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

Commit 3e384ee6c687cb397581ee8f9440fc8220cfac80 (ACPI / PM: Fix
reference counting of power resources) introduced a regression by
causing fan power resources to be turned on and reference counted
unnecessarily during resume, so on some boxes fans are always on
after resume.

Fix the problem by checking if the current device state is different
from the new state before reference counting and turning on power
resources in acpi_power_transition().

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=22932 .

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-and-tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

The reference counting of ACPI power resources is currently broken
for a few reasons.  First, instead of using a simple reference
counter per power resource it uses a list of objects representing
refereces to the given power resource from devices.  This leads to
the second breakage, because it prevents power resources from
being referenced more than once by one device, which is necessary
if the device is configured to signal wakeup.  Namely, when putting
the device into a low power state we first call
acpi_enable_wakeup_device_power() that should reference count power
resources needed for signaling wakeup and then we call
acpi_power_transition() to power off the device.  The latter call
drops references to the device's power resources, possibly including
the ones added by acpi_enable_wakeup_device_power(), so the device
can't signal wakeup as a result.  Apart from this, the locking
in acpi_power_on() and acpi_power_off_device() doesn't prevent
all possible races from happening, which may be problematic for
runtime PM and asynchronous suspend and resume.

Fix the problem by using a counter for power resources reference
counting and putting the evaluation of ACPI _ON and _OFF methods
under the power resource mutex.

Reported-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6:
  gcc-4.6: ACPI: fix unused but set variables in ACPI
  ACPI thermal: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI video: make procfs I/F depend on CONFIG_ACPI_PROCFS
  ACPI processor: remove deprecated ACPI procfs I/F
  ACPI power_resource: remove unused procfs I/F
  ACPI: remove deprecated ACPI procfs I/F
  ACPI: introduce drivers/acpi/sysfs.c
  ACPI: introduce module parameter acpi.aml_debug_output
  ACPI: introduce drivers/acpi/debugfs.c
  ACPI, APEI, ERST debug support
  ACPI, APEI, Manage GHES as platform devices
  ACPI, APEI, Rename CPER and GHES severity constants
  ACPI, APEI, Fix a typo of error path of apei_resources_request
  ACPI / ACPICA: Fix reference counting problems with GPE handlers
  ACPI: Add the check of ADR flag in course of finding ACPI handle for PCI device
  ACPI / Sleep: Drop acpi_suspend_finish()
  ACPI / Sleep: Consolidate suspend and hibernation routines
  ACPI / Wakeup: Simplify enabling of wakeup devices
  ACPI / Sleep: Rework enabling wakeup devices
  ACPI / Sleep: Free NVS copy if suspending of devices fails

Fixed up totally buggered "ACPI: fix unused but set variables in ACPI"
patch that doesn't even compile in the merge.

Thanks to Sedat Dilek <sedat.dilek@googlemail.com> for noticing the
breakage before I even pulled.  And a big "Grrr.." at Len for not even
bothering to compile the tree before asking me to pull.