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ACPI: power: Turn off unused power resources unconditionally

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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 # [1]
Link: https://lore.kernel.org/lkml/20210314000439.3138941-1-luzmaximilian@gmail.com/ # [2]
Tested-by: Wendy Wang <wendy.wang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2021-03-18 19:28:28 +01:00
parent 4b9ee772ea
commit 7e4fdeafa6
1 changed files with 1 additions and 10 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

11
drivers/acpi/power.c
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@ -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);
}