On some systems the ACPI namespace contains device objects that are
not used in certain configurations of the system.  If they start off
in the D0 power state configuration, they will stay in it until the
system reboots, because of the lack of any mechanism possibly causing
their configuration to change.  If that happens, they may prevent
some power resources from being turned off or generally they may
prevent the platform from getting into the deepest low-power states
thus causing some energy to be wasted.

Address this issue by changing the configuration of unused ACPI
device objects to the D3cold power state one after carrying out
the ACPI-based enumeration of devices.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=214091
Link: https://lore.kernel.org/linux-acpi/20211007205126.11769-1-mario.limonciello@amd.com/Reported-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mario Limonciello <mario.limonciello@amd.com>