1 files changed, 36 insertions, 26 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index f6f52c1a2ab..91fed422bae 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -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))
@@ -807,6 +814,7 @@ static int acpi_bus_get_power_flags(struct acpi_device *device)
 	/* TBD: System wake support and resource requirements. */
 
 	device->power.state = ACPI_STATE_UNKNOWN;
+	acpi_bus_get_power(device->handle, &(device->power.state));
 
 	return 0;
 }
@@ -1153,20 +1161,6 @@ static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 }
 
 static int
-acpi_is_child_device(struct acpi_device *device,
-			int (*matcher)(struct acpi_device *))
-{
-	int result = -ENODEV;
-
-	do {
-		if (ACPI_SUCCESS(matcher(device)))
-			return AE_OK;
-	} while ((device = device->parent));
-
-	return result;
-}
-
-static int
 acpi_add_single_object(struct acpi_device **child,
 		       struct acpi_device *parent, acpi_handle handle, int type,
 			struct acpi_bus_ops *ops)
@@ -1221,15 +1215,18 @@ 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:
@@ -1252,6 +1249,16 @@ acpi_add_single_object(struct acpi_device **child,
 	acpi_device_set_id(device, parent, handle, type);
 
 	/*
+	 * The ACPI device is attached to acpi handle before getting
+	 * the power/wakeup/peformance flags. Otherwise OS can't get
+	 * the corresponding ACPI device by the acpi handle in the course
+	 * of getting the power/wakeup/performance flags.
+	 */
+	result = acpi_device_set_context(device, type);
+	if (result)
+		goto end;
+
+	/*
 	 * Power Management
 	 * ----------------
 	 */
@@ -1281,8 +1288,6 @@ acpi_add_single_object(struct acpi_device **child,
 			goto end;
 	}
 
-	if ((result = acpi_device_set_context(device, type)))
-		goto end;
 
 	result = acpi_device_register(device, parent);
 
@@ -1402,7 +1407,12 @@ 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)) {