Replace the combination of kmalloc() and memcpy() in acpi_run_osc()
with a single call to kmemdup().

[rjw: Changelog]
Signed-off-by: Andrei Epure <epure.andrei@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Move ACPI device power management functions from drivers/acpi/bus.c
to drivers/acpi/device_pm.c.

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

The function returning string representations of ACPI device power
states, state_string((), is now static, because it is only used
internally in drivers/acpi/bus.c.  However, it will be used outside
of that file going forward, so rename it to
acpi_power_state_string(), add a kerneldoc comment to it and add its
header to acpi_bus.h.

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

The function used for retrieving ACPI device power states,
__acpi_bus_get_power(), is now static, because it is only used
internally in drivers/acpi/bus.c.  However, it will be used
outside of that file going forward, so rename it to
acpi_device_get_power(), in analogy with acpi_device_set_power(),
add a kerneldoc comment to it and add its header to acpi_bus.h.

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

During power transitions into D3cold from any shallower power states
we are supposed to transition the device into D3hot and remove power
from it afterward, but the current code in acpi_device_set_power()
doesn't work this way.

At the same time, though, we need to be careful enough to preserve
backwards compatibility for systems that don't distinguish between
D3hot and D3cold (e.g. designed before ACPI 4).

Modify acpi_device_set_power() so that it works in accordance with
the expectations in both cases.

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

No power transitioning from D3 state up to a non-D0 state is allowed
so make acpi_device_set_power() fail and complain if such a transition
is attempted.

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

If the caller of acpi_bus_set_power() already has a pointer to the
struct acpi_device object corresponding to the device in question, it
doesn't make sense for it to go through acpi_bus_get_device(), which
may be costly, because it involves acquiring the global ACPI
namespace mutex.

For this reason, export the function operating on struct acpi_device
objects used internally by acpi_bus_set_power(), so that it may be
called instead of acpi_bus_set_power() in the above case, and change
its name to acpi_device_set_power().

Additionally, introduce two inline wrappers for checking ACPI PM
capabilities of devices represented by struct acpi_device objects.

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

The _OSC method may exist in module level code,
so it must be called after ACPI_FULL_INITIALIZATION

On some new platforms with Zero-Power-Optical-Disk-Drive (ZPODD)
support, this fix is necessary to save power.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Tested-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: stable@vger.kernel.org

It turns out that there are ACPI BIOSes defining device objects with
_PSx and without either _PSC or _PRx.  For devices corresponding to
those ACPI objetcs __acpi_bus_get_power() returns ACPI_STATE_UNKNOWN
and their initial power states are regarded as unknown as a result.
If such a device is a parent of another power-manageable device, the
child cannot be put into a low-power state through ACPI, because
__acpi_bus_set_power() refuses to change power states of devices
whose parents' power states are unknown.

To work around this problem, observe that the ACPI power state of
a device cannot be higher-power (lower-number) than the power state
of its parent.  Thus, if the device's _PSC method or the
configuration of its power resources indicates that the device is
in D0, the device's parent has to be in D0 as well.  Consequently,
if the parent's power state is unknown when we've just learned that
its child's power state is D0, we can safely set the parent's
power.state field to ACPI_STATE_D0.

Tested-by: Aaron Lu <aaron.lu@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>