ACPI / PM: Add function for updating device power state consistently

Add function acpi_bus_update_power() for reading the actual power
state of an ACPI device and updating its device->power.state field
in such a way that its power resources' reference counters will
remain consistent with that field.

For this purpose introduce __acpi_bus_set_power() setting the
power state of an ACPI device without updating its
device->power.state field and make acpi_bus_set_power() and
acpi_bus_update_power() use it (acpi_bus_set_power() retains the
current behavior for now).

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

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 4534510905028996beaf78e4c08f26b0a3038c22..19decee72e923603ccadfd2f682472468ee1cdf6 100644 (file)
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -255,44 +255,17 @@ int acpi_bus_get_power(acpi_handle handle, int *state)
 EXPORT_SYMBOL(acpi_bus_get_power);
 
 
-int acpi_bus_set_power(acpi_handle handle, int state)
+static int __acpi_bus_set_power(struct acpi_device *device, int state)
 {
        int result = 0;
        acpi_status status = AE_OK;
-       struct acpi_device *device = NULL;
        char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
 
-
-       result = acpi_bus_get_device(handle, &device);
-       if (result)
-               return result;
-
-       if ((state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
+       if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3))
                return -EINVAL;
 
        /* Make sure this is a valid target state */
 
-       if (!device->flags.power_manageable) {
-               ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device `[%s]' is not power manageable\n",
-                               kobject_name(&device->dev.kobj)));
-               return -ENODEV;
-       }
-       /*
-        * Get device's current power state
-        */
-       if (!acpi_power_nocheck) {
-               /*
-                * Maybe the incorrect power state is returned on the bogus
-                * bios, which is different with the real power state.
-                * For example: the bios returns D0 state and the real power
-                * state is D3. OS expects to set the device to D0 state. In
-                * such case if OS uses the power state returned by the BIOS,
-                * the device can't be transisted to the correct power state.
-                * So if the acpi_power_nocheck is set, it is unnecessary to
-                * get the power state by calling acpi_bus_get_power.
-                */
-               acpi_bus_get_power(device->handle, &device->power.state);
-       }
        if ((state == device->power.state) && !device->flags.force_power_state) {
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device is already at D%d\n",
                                  state));
@@ -362,6 +335,42 @@ int acpi_bus_set_power(acpi_handle handle, int state)
        return result;
 }
 
+
+int acpi_bus_set_power(acpi_handle handle, int state)
+{
+       struct acpi_device *device;
+       int result;
+
+       result = acpi_bus_get_device(handle, &device);
+       if (result)
+               return result;
+
+       if (!device->flags.power_manageable) {
+               ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+                               "Device [%s] is not power manageable\n",
+                               dev_name(&device->dev)));
+               return -ENODEV;
+       }
+
+       /*
+        * Get device's current power state
+        */
+       if (!acpi_power_nocheck) {
+               /*
+                * Maybe the incorrect power state is returned on the bogus
+                * bios, which is different with the real power state.
+                * For example: the bios returns D0 state and the real power
+                * state is D3. OS expects to set the device to D0 state. In
+                * such case if OS uses the power state returned by the BIOS,
+                * the device can't be transisted to the correct power state.
+                * So if the acpi_power_nocheck is set, it is unnecessary to
+                * get the power state by calling acpi_bus_get_power.
+                */
+               __acpi_bus_get_power(device, &device->power.state);
+       }
+
+       return __acpi_bus_set_power(device, state);
+}
 EXPORT_SYMBOL(acpi_bus_set_power);
 
 
@@ -389,6 +398,29 @@ int acpi_bus_init_power(struct acpi_device *device)
 }
 
 
+int acpi_bus_update_power(acpi_handle handle, int *state_p)
+{
+       struct acpi_device *device;
+       int state;
+       int result;
+
+       result = acpi_bus_get_device(handle, &device);
+       if (result)
+               return result;
+
+       result = __acpi_bus_get_power(device, &state);
+       if (result)
+               return result;
+
+       result = __acpi_bus_set_power(device, state);
+       if (!result && state_p)
+               *state_p = state;
+
+       return result;
+}
+EXPORT_SYMBOL_GPL(acpi_bus_update_power);
+
+
 bool acpi_bus_power_manageable(acpi_handle handle)
 {
        struct acpi_device *device;

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index 359ef11725a65da5bf6d07d8fc0cccee33be803f..5d2c4c540063b2d13dad64b9f7d78196ec6a8afc 100644 (file)
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -330,6 +330,7 @@ acpi_status acpi_bus_get_status_handle(acpi_handle handle,
 int acpi_bus_get_status(struct acpi_device *device);
 int acpi_bus_get_power(acpi_handle handle, int *state);
 int acpi_bus_set_power(acpi_handle handle, int state);
+int acpi_bus_update_power(acpi_handle handle, int *state_p);
 bool acpi_bus_power_manageable(acpi_handle handle);
 bool acpi_bus_can_wakeup(acpi_handle handle);
 #ifdef CONFIG_ACPI_PROC_EVENT