1 files changed, 25 insertions, 10 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index ad0679843bd5..89c112ef9e14 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))
@@ -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)) {