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path: root/drivers/acpi/scan.c
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-rw-r--r--drivers/acpi/scan.c28
1 files changed, 19 insertions, 9 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 6d3448895382..1b255e98de4d 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -919,12 +919,9 @@ static void acpi_bus_init_power_state(struct acpi_device *device, int state)
if (buffer.length && package
&& package->type == ACPI_TYPE_PACKAGE
- && package->package.count) {
- int err = acpi_extract_power_resources(package, 0,
- &ps->resources);
- if (!err)
- device->power.flags.power_resources = 1;
- }
+ && package->package.count)
+ acpi_extract_power_resources(package, 0, &ps->resources);
+
ACPI_FREE(buffer.pointer);
}
@@ -971,14 +968,27 @@ static void acpi_bus_get_power_flags(struct acpi_device *device)
acpi_bus_init_power_state(device, i);
INIT_LIST_HEAD(&device->power.states[ACPI_STATE_D3_COLD].resources);
- if (!list_empty(&device->power.states[ACPI_STATE_D3_HOT].resources))
- device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1;
- /* Set defaults for D0 and D3hot states (always valid) */
+ /* Set the defaults for D0 and D3hot (always supported). */
device->power.states[ACPI_STATE_D0].flags.valid = 1;
device->power.states[ACPI_STATE_D0].power = 100;
device->power.states[ACPI_STATE_D3_HOT].flags.valid = 1;
+ /*
+ * Use power resources only if the D0 list of them is populated, because
+ * some platforms may provide _PR3 only to indicate D3cold support and
+ * in those cases the power resources list returned by it may be bogus.
+ */
+ if (!list_empty(&device->power.states[ACPI_STATE_D0].resources)) {
+ device->power.flags.power_resources = 1;
+ /*
+ * D3cold is supported if the D3hot list of power resources is
+ * not empty.
+ */
+ if (!list_empty(&device->power.states[ACPI_STATE_D3_HOT].resources))
+ device->power.states[ACPI_STATE_D3_COLD].flags.valid = 1;
+ }
+
if (acpi_bus_init_power(device))
device->flags.power_manageable = 0;
}