ACPI / PM: Prevent acpi_power_get_inferred_state() from making changes

acpi_power_get_inferred_state() should not update
device->power.state behind the back of its caller, so make it return
the state via a pointer instead.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 7 insertions, 10 deletions

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index d68bd61072b..a9fe8e6bc40 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -222,7 +222,8 @@ int acpi_bus_get_power(acpi_handle handle, int *state)
                  * indirectly (via power resources).
                  */
                 if (device->power.flags.power_resources) {
-                        result = acpi_power_get_inferred_state(device);
+                        result = acpi_power_get_inferred_state(device,
+                                                        &device->power.state);
                         if (result)
                                 return result;
                 } else if (device->power.flags.explicit_get) {
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index a212bfeddf8..2cc01489dcc 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -41,7 +41,7 @@ static inline int acpi_debugfs_init(void) { return 0; }
 int acpi_power_init(void);
 int acpi_device_sleep_wake(struct acpi_device *dev,
                            int enable, int sleep_state, int dev_state);
-int acpi_power_get_inferred_state(struct acpi_device *device);
+int acpi_power_get_inferred_state(struct acpi_device *device, int *state);
 int acpi_power_transition(struct acpi_device *device, int state);
 extern int acpi_power_nocheck;
 
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 4c9c2fb5d98..9bd1b6044b5 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -423,19 +423,16 @@ int acpi_disable_wakeup_device_power(struct acpi_device *dev)
                              Device Power Management
    -------------------------------------------------------------------------- */
 
-int acpi_power_get_inferred_state(struct acpi_device *device)
+int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 {
         int result = 0;
         struct acpi_handle_list *list = NULL;
         int list_state = 0;
         int i = 0;
 
-
-        if (!device)
+        if (!device || !state)
                 return -EINVAL;
 
-        device->power.state = ACPI_STATE_UNKNOWN;
-
         /*
          * We know a device's inferred power state when all the resources
          * required for a given D-state are 'on'.
@@ -450,13 +447,12 @@ int acpi_power_get_inferred_state(struct acpi_device *device)
                         return result;
 
                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
-                        device->power.state = i;
+                        *state = i;
                         return 0;
                 }
         }
 
-        device->power.state = ACPI_STATE_D3;
-
+        *state = ACPI_STATE_D3;
         return 0;
 }