1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 9628652e080c..e0596954290b 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -237,6 +237,16 @@ static int __acpi_bus_get_power(struct acpi_device *device, int *state)
         } else if (result == ACPI_STATE_D3_HOT) {
                 result = ACPI_STATE_D3;
         }
+
+        /*
+         * If we were unsure about the device parent's power state up to this
+         * point, the fact that the device is in D0 implies that the parent has
+         * to be in D0 too.
+         */
+        if (device->parent && device->parent->power.state == ACPI_STATE_UNKNOWN
+            && result == ACPI_STATE_D0)
+                device->parent->power.state = ACPI_STATE_D0;
+
         *state = result;
 
  out: