ACPI: power: Turn off unused power resources unconditionally

According to the ACPI specification (section 7.2.2 in ACPI 6.4), the
OS may evaluate the _OFF method of a power resource that is "off"
already [1], and in particular that can be done in the case of unused
power resources.

Accordingly, modify acpi_turn_off_unused_power_resources() to
evaluate the _OFF method for each of the unused power resources
unconditionally which may help to work around BIOS issues where the
return value of _STA for a power resource does not reflect the
actual state of the power resource [2].

Link: https://uefi.org/specs/ACPI/6.4/07_Power_and_Performance_Mgmt/declaring-a-power-resource-object.html#off
Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.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/power.c b/drivers/acpi/power.c
index 46c38627adddb0a4e2bceec0c900758a905d1d15..bacae6d178ff5af397f556f9c65d38bed0cb9dcd 100644 (file)
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -1005,18 +1005,9 @@ void acpi_turn_off_unused_power_resources(void)
        mutex_lock(&power_resource_list_lock);
 
        list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
-               int result, state;
-
                mutex_lock(&resource->resource_lock);
 
-               result = acpi_power_get_state(resource->device.handle, &state);
-               if (result) {
-                       mutex_unlock(&resource->resource_lock);
-                       continue;
-               }
-
-               if (state == ACPI_POWER_RESOURCE_STATE_ON
-                   && !resource->ref_count) {
+               if (!resource->ref_count) {
                        dev_info(&resource->device.dev, "Turning OFF\n");
                        __acpi_power_off(resource);
                }