linux-toradex.git/drivers/acpi/power.c, branch v4.3.3

Merge branch 'acpi-pm'

2015-09-01T01:38:43+00:00

* acpi-pm:
  ACPI / bus: Move duplicate code to a separate new function
  mfd: Add support for Intel Sunrisepoint LPSS devices
  dmaengine: add a driver for Intel integrated DMA 64-bit
  mfd: make mfd_remove_devices() iterate in reverse order
  driver core: implement device_for_each_child_reverse()
  klist: implement klist_prev()
  Driver core: wakeup the parent device before trying probe
  ACPI / PM: Attach ACPI power domain only once
  PM / QoS: Make it possible to expose device latency tolerance to userspace
  ACPI / PM: Update the copyright notice and description of power.c

ACPI / PM: Update the copyright notice and description of power.c

2015-07-16T00:01:28+00:00

The description and copyright notice of drivers/acpi/power.c is out
of date, so update it as appropriate.

Signed-off-by: Rafael J. Wysocki

ACPI: Remove FSF mailing addresses

2015-07-08T00:27:32+00:00

There is no need to carry potentially outdated Free Software Foundation
mailing address in file headers since the COPYING file includes it.

Signed-off-by: Jarkko Nikula 
Signed-off-by: Rafael J. Wysocki

ACPI / PM: Turn power resources on and off in the right order during resume

2015-05-25T21:59:54+00:00

According to Section 7.2 of ACPI 6.0, power resources should
always be enabled and disabled in order given by the "resourceorder"
field of the corresponding Power Resource objects: "Power Resource
levels are enabled from low values to high values and are disabled
from high values to low values."

However, this is not what happens during system resume, because
in that case the enabling/disabling is carried out in the power
resource registration order which may not reflect the ordering
required by the platform.

For this reason, make the ordering of the global list of all
power resources in the system (used by the system resume code)
reflect the one given by the "resourceorder" attributes of the
Power Resource objects in the ACPI namespace and modify
acpi_resume_power_resources() to walk the list in the reverse
order when turning off the power resources that had been off
before the system was suspended.

Signed-off-by: Rafael J. Wysocki

ACPI / PM: Rework device power management to follow ACPI 6

2015-05-15T23:55:35+00:00

The ACPI 6 specification has made some changes in the device power
management area.  In particular:

 * The D3hot power state is now supposed to be always available
   (instead of D3cold) and D3cold is only regarded as valid if the
   _PR3 object is present for the given device.

 * The required ordering of transitions into power states deeper than
   D0 is now such that for a transition into state Dx the _PSx method
   is supposed to be executed first, if present, and the states of
   the power resources the device depends on are supposed to be
   changed after that.

 * It is now explicitly forbidden to transition devices from
   lower-power (deeper) into higher-power (shallower) power states
   other than D0.

Those changes have been made so the specification reflects the
Windows' device power management code that the vast majority of
systems using ACPI is validated against.

To avoid artificial differences in ACPI device power management
between Windows and Linux, modify the ACPI device power management
code to follow the new specification.  Add comments explaining the
code flow in some unclear places.

This only may affect some real corner cases in which the OS behavior
expected by the firmware is different from the Windows one, but that's
quite unlikely.  The transition ordering change affects transitions
to D1 and D2 which are rarely used (if at all) and into D3hot and
D3cold for devices actually having _PR3, but those are likely to
be validated against Windows anyway.  The other changes may affect
code calling acpi_device_get_power() or acpi_device_update_power()
where ACPI_STATE_D3_HOT may be returned instead of ACPI_STATE_D3_COLD
(that's why the ACPI fan driver needs to be updated too) and since
transitions into ACPI_STATE_D3_HOT may remove power now, it is better
to avoid this one in acpi_pm_device_sleep_state() if the "no power
off" PM QoS flag is set.

The only existing user of acpi_device_can_poweroff() really cares
about the case when _PR3 is present, so the change in that function
should not cause any problems to happen too.

A plus is that PCI_D3hot can be mapped to ACPI_STATE_D3_HOT
now and the compatibility with older systems should be covered
automatically.

In any case, if any real problems result from this, it still will
be better to follow the Windows' behavior (which now is reflected
by the specification too) in general and handle the cases when it
doesn't work via quirks.

Signed-off-by: Rafael J. Wysocki

ACPI / PM: Drop stale comment from acpi_power_transition()

2015-05-08T20:41:05+00:00

An old comment in acpi_power_transition() indicates that support
for ordering power resources needs to be added, but the current
code handles that already.

Drop the comment to avoid confusion.

Signed-off-by: Rafael J. Wysocki

ACPI: Remove duplicate definitions of PREFIX

2014-03-19T01:01:57+00:00

We already have a macro for PREFIX of "ACPI: " in
drivers/acpi/internal.h, so remove the duplicate ones
in ACPI drivers when internal.h is included.

Signed-off-by: Hanjun Guo 
Signed-off-by: Rafael J. Wysocki

ACPI: Clean up inclusions of ACPI header files

2013-12-07T00:03:14+00:00

Replace direct inclusions of ,  and
, which are incorrect, with 
inclusions and remove some inclusions of those files that aren't
necessary.

First of all, ,  and 
should not be included directly from any files that are built for
CONFIG_ACPI unset, because that generally leads to build warnings about
undefined symbols in !CONFIG_ACPI builds.  For CONFIG_ACPI set,
 includes those files and for CONFIG_ACPI unset it
provides stub ACPI symbols to be used in that case.

Second, there are ordering dependencies between those files that always
have to be met.  Namely, it is required that  be included
prior to  so that the acpi_pci_root declarations the
latter depends on are always there.  And  which provides
basic ACPICA type declarations should always be included prior to any other
ACPI headers in CONFIG_ACPI builds.  That also is taken care of including
 as appropriate.

Signed-off-by: Lv Zheng 
Cc: Greg Kroah-Hartman 
Cc: Matthew Garrett 
Cc: Tony Luck 
Cc: "H. Peter Anvin" 
Acked-by: Bjorn Helgaas  (drivers/pci stuff)
Acked-by: Konrad Rzeszutek Wilk  (Xen stuff)
Signed-off-by: Rafael J. Wysocki

ACPI / power: Drop automaitc resume of power resource dependent devices

2013-10-16T21:05:42+00:00

The mechanism causing devices depending on a given power resource
(that is, devices that can be in D0 only if that power resource is
on) to be resumed automatically when the power resource is turned
on (and their "inferred" power state becomes D0 as a result) is
inherently racy and in fact unnecessary.

It is racy, because if the power resource is turned on and then
immediately off, the device resume triggered by the first transition
to "on" may still happen, causing the power resource to be turned
on again.  That again will trigger the "resume of dependent devices"
mechanism, but if the devices in question are not in use, they will
be suspended in the meantime causing the power resource to be turned
off.  However, the "resume of dependent devices" will next resume
them again and so on.  In some cases (USB port PM in particular) that
leads to an endless busy loop of flipping the resource on and off
continuously.

It is needless, because whoever turns a power resource on will most
likely turn it off at some point and the devices that go into "D0"
as a result of turning it on will then go back into D3cold
(generally, the state they were in before).

Moreover, turning on all power resources a device needs to go into
D0 is not sufficient for a full transition into D0 in general.
Namely, _PS0 may need to be executed in addition to that in some
cases.  This means that the whole rationale of the "resume of
dependent devices" mechanism was incorrect to begin with and it's
best to remove it entirely.

Signed-off-by: Rafael J. Wysocki

ACPI / power: Release resource_lock after acpi_power_get_state() return error

2013-10-15T22:26:42+00:00

In acpi_resume_power_resources() resource_lock should be released
when acpi_power_get_state() fails and before passing to next power
resource on the list.

Signed-off-by: Lan Tianyu 
Signed-off-by: Rafael J. Wysocki