ACPI: scan: Turn off unused power resources during initialization

It is reported that on certain platforms there are power resources
that are not associated with any devices physically present in the
platform.  Those power resources are expected to be turned off by
the OS in accordance with the ACPI specification (section 7.3 of
ACPI 6.4) which currently is not done by Linux and that may lead
to obscure issues.

For instance, leaving those power resources in the "on" state may
prevent the platform from reaching the lowest power state in
suspend-to-idle which leads to excessive power draw.

For this reason, turn all of the unused ACPI power resources off
at the end of the initial namespace scan for devices in analogy with
resume from suspend-to-RAM.

Link: https://uefi.org/specs/ACPI/6.4/07_Power_and_Performance_Mgmt/device-power-management-objects.html
Reported-by: David Box <david.e.box@linux.intel.com>
Tested-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index e6a5d997241c43d803d9758b01328db8b6cdb0cc..9fcefcdc1dbe07965b14d3ba530d9b8b9bc0b60e 100644 (file)
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -139,6 +139,7 @@ int acpi_device_sleep_wake(struct acpi_device *dev,
 int acpi_power_get_inferred_state(struct acpi_device *device, int *state);
 int acpi_power_on_resources(struct acpi_device *device, int state);
 int acpi_power_transition(struct acpi_device *device, int state);
+void acpi_turn_off_unused_power_resources(void);
 
 /* --------------------------------------------------------------------------
                               Device Power Management

diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 9b608b55d2b29545ccd32965bbdc5636af49252b..46c38627adddb0a4e2bceec0c900758a905d1d15 100644 (file)
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -996,6 +996,7 @@ void acpi_resume_power_resources(void)
 
        mutex_unlock(&power_resource_list_lock);
 }
+#endif
 
 void acpi_turn_off_unused_power_resources(void)
 {
@@ -1025,4 +1026,3 @@ void acpi_turn_off_unused_power_resources(void)
 
        mutex_unlock(&power_resource_list_lock);
 }
-#endif

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index a184529d8fa402f077790cbfa04094e7724c6c9a..1584c9e463bdf61b8cf3b099b64f35d569263c2e 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2360,6 +2360,8 @@ int __init acpi_scan_init(void)
                }
        }
 
+       acpi_turn_off_unused_power_resources();
+
        acpi_scan_initialized = true;
 
  out:

diff --git a/drivers/acpi/sleep.h b/drivers/acpi/sleep.h
index 1856f76ac83f73451715af33f5488f2420b7fca9..7fe41ee489d6123c2fec04a6672ef25f1c04cbce 100644 (file)
--- a/drivers/acpi/sleep.h
+++ b/drivers/acpi/sleep.h
@@ -8,7 +8,6 @@ extern struct list_head acpi_wakeup_device_list;
 extern struct mutex acpi_device_lock;
 
 extern void acpi_resume_power_resources(void);
-extern void acpi_turn_off_unused_power_resources(void);
 
 static inline acpi_status acpi_set_waking_vector(u32 wakeup_address)
 {