ACPI : Load device driver according to the status of acpi device
[linux-2.6.git] / drivers / acpi / scan.c
index ad06798..89c112e 100644 (file)
@@ -276,6 +276,13 @@ int acpi_match_device_ids(struct acpi_device *device,
 {
        const struct acpi_device_id *id;
 
+       /*
+        * If the device is not present, it is unnecessary to load device
+        * driver for it.
+        */
+       if (!device->status.present)
+               return -ENODEV;
+
        if (device->flags.hardware_id) {
                for (id = ids; id->id[0]; id++) {
                        if (!strcmp((char*)id->id, device->pnp.hardware_id))
@@ -1222,15 +1229,18 @@ acpi_add_single_object(struct acpi_device **child,
                        result = -ENODEV;
                        goto end;
                }
-               if (!device->status.present) {
-                       /* Bay and dock should be handled even if absent */
-                       if (!ACPI_SUCCESS(
-                            acpi_is_child_device(device, acpi_bay_match)) &&
-                           !ACPI_SUCCESS(
-                            acpi_is_child_device(device, acpi_dock_match))) {
-                                       result = -ENODEV;
-                                       goto end;
-                       }
+               /*
+                * When the device is neither present nor functional, the
+                * device should not be added to Linux ACPI device tree.
+                * When the status of the device is not present but functinal,
+                * it should be added to Linux ACPI tree. For example : bay
+                * device , dock device.
+                * In such conditions it is unncessary to check whether it is
+                * bay device or dock device.
+                */
+               if (!device->status.present && !device->status.functional) {
+                       result = -ENODEV;
+                       goto end;
                }
                break;
        default:
@@ -1411,7 +1421,12 @@ static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
                 * TBD: Need notifications and other detection mechanisms
                 *      in place before we can fully implement this.
                 */
-               if (child->status.present) {
+                /*
+                * When the device is not present but functional, it is also
+                * necessary to scan the children of this device.
+                */
+               if (child->status.present || (!child->status.present &&
+                                       child->status.functional)) {
                        status = acpi_get_next_object(ACPI_TYPE_ANY, chandle,
                                                      NULL, NULL);
                        if (ACPI_SUCCESS(status)) {