include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit...
[safe/jmp/linux-2.6] / drivers / acpi / scan.c
index f205b36..0261b11 100644 (file)
@@ -4,10 +4,12 @@
 
 #include <linux/module.h>
 #include <linux/init.h>
+#include <linux/slab.h>
 #include <linux/kernel.h>
 #include <linux/acpi.h>
 #include <linux/signal.h>
 #include <linux/kthread.h>
+#include <linux/dmi.h>
 
 #include <acpi/acpi_drivers.h>
 
@@ -22,6 +24,8 @@ extern struct acpi_device *acpi_root;
 #define ACPI_BUS_HID                   "LNXSYBUS"
 #define ACPI_BUS_DEVICE_NAME           "System Bus"
 
+#define ACPI_IS_ROOT_DEVICE(device)    (!(device)->parent)
+
 static LIST_HEAD(acpi_device_list);
 static LIST_HEAD(acpi_bus_id_list);
 DEFINE_MUTEX(acpi_device_lock);
@@ -43,40 +47,19 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
 {
        int len;
        int count;
-
-       if (!acpi_dev->flags.hardware_id && !acpi_dev->flags.compatible_ids)
-               return -ENODEV;
+       struct acpi_hardware_id *id;
 
        len = snprintf(modalias, size, "acpi:");
        size -= len;
 
-       if (acpi_dev->flags.hardware_id) {
-               count = snprintf(&modalias[len], size, "%s:",
-                                acpi_dev->pnp.hardware_id);
+       list_for_each_entry(id, &acpi_dev->pnp.ids, list) {
+               count = snprintf(&modalias[len], size, "%s:", id->id);
                if (count < 0 || count >= size)
                        return -EINVAL;
                len += count;
                size -= count;
        }
 
-       if (acpi_dev->flags.compatible_ids) {
-               struct acpica_device_id_list *cid_list;
-               int i;
-
-               cid_list = acpi_dev->pnp.cid_list;
-               for (i = 0; i < cid_list->count; i++) {
-                       count = snprintf(&modalias[len], size, "%s:",
-                                        cid_list->ids[i].string);
-                       if (count < 0 || count >= size) {
-                               printk(KERN_ERR PREFIX "%s cid[%i] exceeds event buffer size",
-                                      acpi_dev->pnp.device_name, i);
-                               break;
-                       }
-                       len += count;
-                       size -= count;
-               }
-       }
-
        modalias[len] = '\0';
        return len;
 }
@@ -183,7 +166,7 @@ static ssize_t
 acpi_device_hid_show(struct device *dev, struct device_attribute *attr, char *buf) {
        struct acpi_device *acpi_dev = to_acpi_device(dev);
 
-       return sprintf(buf, "%s\n", acpi_dev->pnp.hardware_id);
+       return sprintf(buf, "%s\n", acpi_device_hid(acpi_dev));
 }
 static DEVICE_ATTR(hid, 0444, acpi_device_hid_show, NULL);
 
@@ -219,17 +202,13 @@ static int acpi_device_setup_files(struct acpi_device *dev)
                        goto end;
        }
 
-       if (dev->flags.hardware_id) {
-               result = device_create_file(&dev->dev, &dev_attr_hid);
-               if (result)
-                       goto end;
-       }
+       result = device_create_file(&dev->dev, &dev_attr_hid);
+       if (result)
+               goto end;
 
-       if (dev->flags.hardware_id || dev->flags.compatible_ids) {
-               result = device_create_file(&dev->dev, &dev_attr_modalias);
-               if (result)
-                       goto end;
-       }
+       result = device_create_file(&dev->dev, &dev_attr_modalias);
+       if (result)
+               goto end;
 
         /*
          * If device has _EJ0, 'eject' file is created that is used to trigger
@@ -255,11 +234,8 @@ static void acpi_device_remove_files(struct acpi_device *dev)
        if (ACPI_SUCCESS(status))
                device_remove_file(&dev->dev, &dev_attr_eject);
 
-       if (dev->flags.hardware_id || dev->flags.compatible_ids)
-               device_remove_file(&dev->dev, &dev_attr_modalias);
-
-       if (dev->flags.hardware_id)
-               device_remove_file(&dev->dev, &dev_attr_hid);
+       device_remove_file(&dev->dev, &dev_attr_modalias);
+       device_remove_file(&dev->dev, &dev_attr_hid);
        if (dev->handle)
                device_remove_file(&dev->dev, &dev_attr_path);
 }
@@ -271,6 +247,7 @@ int acpi_match_device_ids(struct acpi_device *device,
                          const struct acpi_device_id *ids)
 {
        const struct acpi_device_id *id;
+       struct acpi_hardware_id *hwid;
 
        /*
         * If the device is not present, it is unnecessary to load device
@@ -279,40 +256,30 @@ int acpi_match_device_ids(struct acpi_device *device,
        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))
+       for (id = ids; id->id[0]; id++)
+               list_for_each_entry(hwid, &device->pnp.ids, list)
+                       if (!strcmp((char *) id->id, hwid->id))
                                return 0;
-               }
-       }
-
-       if (device->flags.compatible_ids) {
-               struct acpica_device_id_list *cid_list = device->pnp.cid_list;
-               int i;
-
-               for (id = ids; id->id[0]; id++) {
-                       /* compare multiple _CID entries against driver ids */
-                       for (i = 0; i < cid_list->count; i++) {
-                               if (!strcmp((char*)id->id,
-                                           cid_list->ids[i].string))
-                                       return 0;
-                       }
-               }
-       }
 
        return -ENOENT;
 }
 EXPORT_SYMBOL(acpi_match_device_ids);
 
+static void acpi_free_ids(struct acpi_device *device)
+{
+       struct acpi_hardware_id *id, *tmp;
+
+       list_for_each_entry_safe(id, tmp, &device->pnp.ids, list) {
+               kfree(id->id);
+               kfree(id);
+       }
+}
+
 static void acpi_device_release(struct device *dev)
 {
        struct acpi_device *acpi_dev = to_acpi_device(dev);
 
-       kfree(acpi_dev->pnp.cid_list);
-       if (acpi_dev->flags.hardware_id)
-               kfree(acpi_dev->pnp.hardware_id);
-       if (acpi_dev->flags.unique_id)
-               kfree(acpi_dev->pnp.unique_id);
+       acpi_free_ids(acpi_dev);
        kfree(acpi_dev);
 }
 
@@ -499,8 +466,9 @@ static int acpi_device_register(struct acpi_device *device)
         * If failed, create one and link it into acpi_bus_id_list
         */
        list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node) {
-               if(!strcmp(acpi_device_bus_id->bus_id, device->flags.hardware_id? device->pnp.hardware_id : "device")) {
-                       acpi_device_bus_id->instance_no ++;
+               if (!strcmp(acpi_device_bus_id->bus_id,
+                           acpi_device_hid(device))) {
+                       acpi_device_bus_id->instance_no++;
                        found = 1;
                        kfree(new_bus_id);
                        break;
@@ -508,7 +476,7 @@ static int acpi_device_register(struct acpi_device *device)
        }
        if (!found) {
                acpi_device_bus_id = new_bus_id;
-               strcpy(acpi_device_bus_id->bus_id, device->flags.hardware_id ? device->pnp.hardware_id : "device");
+               strcpy(acpi_device_bus_id->bus_id, acpi_device_hid(device));
                acpi_device_bus_id->instance_no = 0;
                list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
        }
@@ -775,19 +743,40 @@ acpi_bus_extract_wakeup_device_power_package(struct acpi_device *device,
        return AE_OK;
 }
 
-static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
+static void acpi_bus_set_run_wake_flags(struct acpi_device *device)
 {
-       acpi_status status = 0;
-       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
-       union acpi_object *package = NULL;
-       int psw_error;
-
        struct acpi_device_id button_device_ids[] = {
                {"PNP0C0D", 0},
                {"PNP0C0C", 0},
                {"PNP0C0E", 0},
                {"", 0},
        };
+       acpi_status status;
+       acpi_event_status event_status;
+
+       device->wakeup.run_wake_count = 0;
+       device->wakeup.flags.notifier_present = 0;
+
+       /* Power button, Lid switch always enable wakeup */
+       if (!acpi_match_device_ids(device, button_device_ids)) {
+               device->wakeup.flags.run_wake = 1;
+               device->wakeup.flags.always_enabled = 1;
+               return;
+       }
+
+       status = acpi_get_gpe_status(NULL, device->wakeup.gpe_number,
+                                       ACPI_NOT_ISR, &event_status);
+       if (status == AE_OK)
+               device->wakeup.flags.run_wake =
+                               !!(event_status & ACPI_EVENT_FLAG_HANDLE);
+}
+
+static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
+{
+       acpi_status status = 0;
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *package = NULL;
+       int psw_error;
 
        /* _PRW */
        status = acpi_evaluate_object(device->handle, "_PRW", NULL, &buffer);
@@ -807,6 +796,7 @@ static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
 
        device->wakeup.flags.valid = 1;
        device->wakeup.prepare_count = 0;
+       acpi_bus_set_run_wake_flags(device);
        /* Call _PSW/_DSW object to disable its ability to wake the sleeping
         * system for the ACPI device with the _PRW object.
         * The _PSW object is depreciated in ACPI 3.0 and is replaced by _DSW.
@@ -818,10 +808,6 @@ static int acpi_bus_get_wakeup_device_flags(struct acpi_device *device)
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                "error in _DSW or _PSW evaluation\n"));
 
-       /* Power button, Lid switch always enable wakeup */
-       if (!acpi_match_device_ids(device, button_device_ids))
-               device->wakeup.flags.run_wake = 1;
-
 end:
        if (ACPI_FAILURE(status))
                device->flags.wake_capable = 0;
@@ -901,11 +887,6 @@ static int acpi_bus_get_flags(struct acpi_device *device)
        if (ACPI_SUCCESS(status))
                device->flags.dynamic_status = 1;
 
-       /* Presence of _CID indicates 'compatible_ids' */
-       status = acpi_get_handle(device->handle, "_CID", &temp);
-       if (ACPI_SUCCESS(status))
-               device->flags.compatible_ids = 1;
-
        /* Presence of _RMV indicates 'removable' */
        status = acpi_get_handle(device->handle, "_RMV", &temp);
        if (ACPI_SUCCESS(status))
@@ -955,10 +936,12 @@ static void acpi_device_get_busid(struct acpi_device *device)
         * The device's Bus ID is simply the object name.
         * TBD: Shouldn't this value be unique (within the ACPI namespace)?
         */
-       switch (device->device_type) {
-       case ACPI_BUS_TYPE_SYSTEM:
+       if (ACPI_IS_ROOT_DEVICE(device)) {
                strcpy(device->pnp.bus_id, "ACPI");
-               break;
+               return;
+       }
+
+       switch (device->device_type) {
        case ACPI_BUS_TYPE_POWER_BUTTON:
                strcpy(device->pnp.bus_id, "PWRF");
                break;
@@ -1024,75 +1007,88 @@ static int acpi_dock_match(struct acpi_device *device)
        return acpi_get_handle(device->handle, "_DCK", &tmp);
 }
 
-static struct acpica_device_id_list*
-acpi_add_cid(
-       struct acpi_device_info         *info,
-       struct acpica_device_id         *new_cid)
+char *acpi_device_hid(struct acpi_device *device)
 {
-       struct acpica_device_id_list    *cid;
-       char                            *next_id_string;
-       acpi_size                       cid_length;
-       acpi_size                       new_cid_length;
-       u32                             i;
+       struct acpi_hardware_id *hid;
 
+       hid = list_first_entry(&device->pnp.ids, struct acpi_hardware_id, list);
+       return hid->id;
+}
+EXPORT_SYMBOL(acpi_device_hid);
 
-       /* Allocate new CID list with room for the new CID */
+static void acpi_add_id(struct acpi_device *device, const char *dev_id)
+{
+       struct acpi_hardware_id *id;
 
-       if (!new_cid)
-               new_cid_length = info->compatible_id_list.list_size;
-       else if (info->compatible_id_list.list_size)
-               new_cid_length = info->compatible_id_list.list_size +
-                       new_cid->length + sizeof(struct acpica_device_id);
-       else
-               new_cid_length = sizeof(struct acpica_device_id_list) + new_cid->length;
+       id = kmalloc(sizeof(*id), GFP_KERNEL);
+       if (!id)
+               return;
 
-       cid = ACPI_ALLOCATE_ZEROED(new_cid_length);
-       if (!cid) {
-               return NULL;
+       id->id = kmalloc(strlen(dev_id) + 1, GFP_KERNEL);
+       if (!id->id) {
+               kfree(id);
+               return;
        }
 
-       cid->list_size = new_cid_length;
-       cid->count = info->compatible_id_list.count;
-       if (new_cid)
-               cid->count++;
-       next_id_string = (char *) cid->ids + (cid->count * sizeof(struct acpica_device_id));
-
-       /* Copy all existing CIDs */
-
-       for (i = 0; i < info->compatible_id_list.count; i++) {
-               cid_length = info->compatible_id_list.ids[i].length;
-               cid->ids[i].string = next_id_string;
-               cid->ids[i].length = cid_length;
-
-               ACPI_MEMCPY(next_id_string, info->compatible_id_list.ids[i].string,
-                       cid_length);
+       strcpy(id->id, dev_id);
+       list_add_tail(&id->list, &device->pnp.ids);
+}
 
-               next_id_string += cid_length;
-       }
+/*
+ * Old IBM workstations have a DSDT bug wherein the SMBus object
+ * lacks the SMBUS01 HID and the methods do not have the necessary "_"
+ * prefix.  Work around this.
+ */
+static int acpi_ibm_smbus_match(struct acpi_device *device)
+{
+       acpi_handle h_dummy;
+       struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL};
+       int result;
 
-       /* Append the new CID */
+       if (!dmi_name_in_vendors("IBM"))
+               return -ENODEV;
 
-       if (new_cid) {
-               cid->ids[i].string = next_id_string;
-               cid->ids[i].length = new_cid->length;
+       /* Look for SMBS object */
+       result = acpi_get_name(device->handle, ACPI_SINGLE_NAME, &path);
+       if (result)
+               return result;
 
-               ACPI_MEMCPY(next_id_string, new_cid->string, new_cid->length);
+       if (strcmp("SMBS", path.pointer)) {
+               result = -ENODEV;
+               goto out;
        }
 
-       return cid;
+       /* Does it have the necessary (but misnamed) methods? */
+       result = -ENODEV;
+       if (ACPI_SUCCESS(acpi_get_handle(device->handle, "SBI", &h_dummy)) &&
+           ACPI_SUCCESS(acpi_get_handle(device->handle, "SBR", &h_dummy)) &&
+           ACPI_SUCCESS(acpi_get_handle(device->handle, "SBW", &h_dummy)))
+               result = 0;
+out:
+       kfree(path.pointer);
+       return result;
 }
 
 static void acpi_device_set_id(struct acpi_device *device)
 {
-       struct acpi_device_info *info = NULL;
-       char *hid = NULL;
-       char *uid = NULL;
-       struct acpica_device_id_list *cid_list = NULL;
-       char *cid_add = NULL;
        acpi_status status;
+       struct acpi_device_info *info;
+       struct acpica_device_id_list *cid_list;
+       int i;
 
        switch (device->device_type) {
        case ACPI_BUS_TYPE_DEVICE:
+               if (ACPI_IS_ROOT_DEVICE(device)) {
+                       acpi_add_id(device, ACPI_SYSTEM_HID);
+                       break;
+               } else if (ACPI_IS_ROOT_DEVICE(device->parent)) {
+                       /* \_SB_, the only root-level namespace device */
+                       acpi_add_id(device, ACPI_BUS_HID);
+                       strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
+                       strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
+                       break;
+               }
+
                status = acpi_get_object_info(device->handle, &info);
                if (ACPI_FAILURE(status)) {
                        printk(KERN_ERR PREFIX "%s: Error reading device info\n", __func__);
@@ -1100,102 +1096,59 @@ static void acpi_device_set_id(struct acpi_device *device)
                }
 
                if (info->valid & ACPI_VALID_HID)
-                       hid = info->hardware_id.string;
-               if (info->valid & ACPI_VALID_UID)
-                       uid = info->unique_id.string;
-               if (info->valid & ACPI_VALID_CID)
+                       acpi_add_id(device, info->hardware_id.string);
+               if (info->valid & ACPI_VALID_CID) {
                        cid_list = &info->compatible_id_list;
+                       for (i = 0; i < cid_list->count; i++)
+                               acpi_add_id(device, cid_list->ids[i].string);
+               }
                if (info->valid & ACPI_VALID_ADR) {
                        device->pnp.bus_address = info->address;
                        device->flags.bus_address = 1;
                }
 
-               /* If we have a video/bay/dock device, add our selfdefined
-                  HID to the CID list. Like that the video/bay/dock drivers
-                  will get autoloaded and the device might still match
-                  against another driver.
-               */
+               kfree(info);
+
+               /*
+                * Some devices don't reliably have _HIDs & _CIDs, so add
+                * synthetic HIDs to make sure drivers can find them.
+                */
                if (acpi_is_video_device(device))
-                       cid_add = ACPI_VIDEO_HID;
+                       acpi_add_id(device, ACPI_VIDEO_HID);
                else if (ACPI_SUCCESS(acpi_bay_match(device)))
-                       cid_add = ACPI_BAY_HID;
+                       acpi_add_id(device, ACPI_BAY_HID);
                else if (ACPI_SUCCESS(acpi_dock_match(device)))
-                       cid_add = ACPI_DOCK_HID;
+                       acpi_add_id(device, ACPI_DOCK_HID);
+               else if (!acpi_ibm_smbus_match(device))
+                       acpi_add_id(device, ACPI_SMBUS_IBM_HID);
 
                break;
        case ACPI_BUS_TYPE_POWER:
-               hid = ACPI_POWER_HID;
+               acpi_add_id(device, ACPI_POWER_HID);
                break;
        case ACPI_BUS_TYPE_PROCESSOR:
-               hid = ACPI_PROCESSOR_OBJECT_HID;
-               break;
-       case ACPI_BUS_TYPE_SYSTEM:
-               hid = ACPI_SYSTEM_HID;
+               acpi_add_id(device, ACPI_PROCESSOR_OBJECT_HID);
                break;
        case ACPI_BUS_TYPE_THERMAL:
-               hid = ACPI_THERMAL_HID;
+               acpi_add_id(device, ACPI_THERMAL_HID);
                break;
        case ACPI_BUS_TYPE_POWER_BUTTON:
-               hid = ACPI_BUTTON_HID_POWERF;
+               acpi_add_id(device, ACPI_BUTTON_HID_POWERF);
                break;
        case ACPI_BUS_TYPE_SLEEP_BUTTON:
-               hid = ACPI_BUTTON_HID_SLEEPF;
+               acpi_add_id(device, ACPI_BUTTON_HID_SLEEPF);
                break;
        }
 
        /*
-        * \_SB
-        * ----
-        * Fix for the system root bus device -- the only root-level device.
+        * We build acpi_devices for some objects that don't have _HID or _CID,
+        * e.g., PCI bridges and slots.  Drivers can't bind to these objects,
+        * but we do use them indirectly by traversing the acpi_device tree.
+        * This generic ID isn't useful for driver binding, but it provides
+        * the useful property that "every acpi_device has an ID."
         */
-       if (((acpi_handle)device->parent == ACPI_ROOT_OBJECT) &&
-            (device->device_type == ACPI_BUS_TYPE_DEVICE)) {
-               hid = ACPI_BUS_HID;
-               strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);
-               strcpy(device->pnp.device_class, ACPI_BUS_CLASS);
-       }
-
-       if (hid) {
-               device->pnp.hardware_id = ACPI_ALLOCATE_ZEROED(strlen (hid) + 1);
-               if (device->pnp.hardware_id) {
-                       strcpy(device->pnp.hardware_id, hid);
-                       device->flags.hardware_id = 1;
-               }
-       }
-       if (!device->flags.hardware_id)
-               device->pnp.hardware_id = "";
-
-       if (uid) {
-               device->pnp.unique_id = ACPI_ALLOCATE_ZEROED(strlen (uid) + 1);
-               if (device->pnp.unique_id) {
-                       strcpy(device->pnp.unique_id, uid);
-                       device->flags.unique_id = 1;
-               }
-       }
-       if (!device->flags.unique_id)
-               device->pnp.unique_id = "";
-
-       if (cid_list || cid_add) {
-               struct acpica_device_id_list *list;
-
-               if (cid_add) {
-                       struct acpica_device_id cid;
-                       cid.length = strlen (cid_add) + 1;
-                       cid.string = cid_add;
-
-                       list = acpi_add_cid(info, &cid);
-               } else {
-                       list = acpi_add_cid(info, NULL);
-               }
-
-               if (list) {
-                       device->pnp.cid_list = list;
-                       if (cid_add)
-                               device->flags.compatible_ids = 1;
-               }
-       }
-
-       kfree(info);
+       if (list_empty(&device->pnp.ids))
+               acpi_add_id(device, "device");
 }
 
 static int acpi_device_set_context(struct acpi_device *device)
@@ -1246,6 +1199,7 @@ static int acpi_bus_remove(struct acpi_device *dev, int rmdevice)
 
 static int acpi_add_single_object(struct acpi_device **child,
                                  acpi_handle handle, int type,
+                                 unsigned long long sta,
                                  struct acpi_bus_ops *ops)
 {
        int result;
@@ -1258,74 +1212,30 @@ static int acpi_add_single_object(struct acpi_device **child,
                return -ENOMEM;
        }
 
+       INIT_LIST_HEAD(&device->pnp.ids);
        device->device_type = type;
        device->handle = handle;
        device->parent = acpi_bus_get_parent(handle);
        device->bus_ops = *ops; /* workround for not call .start */
+       STRUCT_TO_INT(device->status) = sta;
 
        acpi_device_get_busid(device);
 
        /*
         * Flags
         * -----
-        * Get prior to calling acpi_bus_get_status() so we know whether
-        * or not _STA is present.  Note that we only look for object
-        * handles -- cannot evaluate objects until we know the device is
-        * present and properly initialized.
+        * Note that we only look for object handles -- cannot evaluate objects
+        * until we know the device is present and properly initialized.
         */
        result = acpi_bus_get_flags(device);
        if (result)
                goto end;
 
        /*
-        * Status
-        * ------
-        * See if the device is present.  We always assume that non-Device
-        * and non-Processor objects (e.g. thermal zones, power resources,
-        * etc.) are present, functioning, etc. (at least when parent object
-        * is present).  Note that _STA has a different meaning for some
-        * objects (e.g. power resources) so we need to be careful how we use
-        * it.
-        */
-       switch (type) {
-       case ACPI_BUS_TYPE_PROCESSOR:
-       case ACPI_BUS_TYPE_DEVICE:
-               result = acpi_bus_get_status(device);
-               if (ACPI_FAILURE(result)) {
-                       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:
-               STRUCT_TO_INT(device->status) =
-                   ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
-                   ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING;
-               break;
-       }
-
-       /*
         * Initialize Device
         * -----------------
         * TBD: Synch with Core's enumeration/initialization process.
         */
-
-       /*
-        * Hardware ID, Unique ID, & Bus Address
-        * -------------------------------------
-        */
        acpi_device_set_id(device);
 
        /*
@@ -1387,157 +1297,145 @@ end:
        return result;
 }
 
-static int acpi_bus_scan(struct acpi_device *start, struct acpi_bus_ops *ops)
+#define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
+                         ACPI_STA_DEVICE_UI      | ACPI_STA_DEVICE_FUNCTIONING)
+
+static int acpi_bus_type_and_status(acpi_handle handle, int *type,
+                                   unsigned long long *sta)
 {
-       acpi_status status = AE_OK;
-       struct acpi_device *parent = NULL;
-       struct acpi_device *child = NULL;
-       acpi_handle phandle = NULL;
-       acpi_handle chandle = NULL;
-       acpi_object_type type = 0;
-       u32 level = 1;
+       acpi_status status;
+       acpi_object_type acpi_type;
 
+       status = acpi_get_type(handle, &acpi_type);
+       if (ACPI_FAILURE(status))
+               return -ENODEV;
 
-       if (!start)
-               return -EINVAL;
+       switch (acpi_type) {
+       case ACPI_TYPE_ANY:             /* for ACPI_ROOT_OBJECT */
+       case ACPI_TYPE_DEVICE:
+               *type = ACPI_BUS_TYPE_DEVICE;
+               status = acpi_bus_get_status_handle(handle, sta);
+               if (ACPI_FAILURE(status))
+                       return -ENODEV;
+               break;
+       case ACPI_TYPE_PROCESSOR:
+               *type = ACPI_BUS_TYPE_PROCESSOR;
+               status = acpi_bus_get_status_handle(handle, sta);
+               if (ACPI_FAILURE(status))
+                       return -ENODEV;
+               break;
+       case ACPI_TYPE_THERMAL:
+               *type = ACPI_BUS_TYPE_THERMAL;
+               *sta = ACPI_STA_DEFAULT;
+               break;
+       case ACPI_TYPE_POWER:
+               *type = ACPI_BUS_TYPE_POWER;
+               *sta = ACPI_STA_DEFAULT;
+               break;
+       default:
+               return -ENODEV;
+       }
 
-       parent = start;
-       phandle = start->handle;
+       return 0;
+}
 
-       /*
-        * Parse through the ACPI namespace, identify all 'devices', and
-        * create a new 'struct acpi_device' for each.
-        */
-       while ((level > 0) && parent) {
+static acpi_status acpi_bus_check_add(acpi_handle handle, u32 lvl,
+                                     void *context, void **return_value)
+{
+       struct acpi_bus_ops *ops = context;
+       int type;
+       unsigned long long sta;
+       struct acpi_device *device;
+       acpi_status status;
+       int result;
 
-               status = acpi_get_next_object(ACPI_TYPE_ANY, phandle,
-                                             chandle, &chandle);
+       result = acpi_bus_type_and_status(handle, &type, &sta);
+       if (result)
+               return AE_OK;
 
-               /*
-                * If this scope is exhausted then move our way back up.
-                */
-               if (ACPI_FAILURE(status)) {
-                       level--;
-                       chandle = phandle;
-                       acpi_get_parent(phandle, &phandle);
-                       if (parent->parent)
-                               parent = parent->parent;
-                       continue;
-               }
+       if (!(sta & ACPI_STA_DEVICE_PRESENT) &&
+           !(sta & ACPI_STA_DEVICE_FUNCTIONING))
+               return AE_CTRL_DEPTH;
 
-               status = acpi_get_type(chandle, &type);
-               if (ACPI_FAILURE(status))
-                       continue;
+       /*
+        * We may already have an acpi_device from a previous enumeration.  If
+        * so, we needn't add it again, but we may still have to start it.
+        */
+       device = NULL;
+       acpi_bus_get_device(handle, &device);
+       if (ops->acpi_op_add && !device)
+               acpi_add_single_object(&device, handle, type, sta, ops);
 
-               /*
-                * If this is a scope object then parse it (depth-first).
-                */
-               if (type == ACPI_TYPE_LOCAL_SCOPE) {
-                       level++;
-                       phandle = chandle;
-                       chandle = NULL;
-                       continue;
-               }
+       if (!device)
+               return AE_CTRL_DEPTH;
 
-               /*
-                * We're only interested in objects that we consider 'devices'.
-                */
-               switch (type) {
-               case ACPI_TYPE_DEVICE:
-                       type = ACPI_BUS_TYPE_DEVICE;
-                       break;
-               case ACPI_TYPE_PROCESSOR:
-                       type = ACPI_BUS_TYPE_PROCESSOR;
-                       break;
-               case ACPI_TYPE_THERMAL:
-                       type = ACPI_BUS_TYPE_THERMAL;
-                       break;
-               case ACPI_TYPE_POWER:
-                       type = ACPI_BUS_TYPE_POWER;
-                       break;
-               default:
-                       continue;
-               }
+       if (ops->acpi_op_start && !(ops->acpi_op_add)) {
+               status = acpi_start_single_object(device);
+               if (ACPI_FAILURE(status))
+                       return AE_CTRL_DEPTH;
+       }
 
-               if (ops->acpi_op_add)
-                       status = acpi_add_single_object(&child, chandle, type,
-                                                       ops);
-               else
-                       status = acpi_bus_get_device(chandle, &child);
+       if (!*return_value)
+               *return_value = device;
+       return AE_OK;
+}
 
-               if (ACPI_FAILURE(status))
-                       continue;
+static int acpi_bus_scan(acpi_handle handle, struct acpi_bus_ops *ops,
+                        struct acpi_device **child)
+{
+       acpi_status status;
+       void *device = NULL;
 
-               if (ops->acpi_op_start && !(ops->acpi_op_add)) {
-                       status = acpi_start_single_object(child);
-                       if (ACPI_FAILURE(status))
-                               continue;
-               }
+       status = acpi_bus_check_add(handle, 0, ops, &device);
+       if (ACPI_SUCCESS(status))
+               acpi_walk_namespace(ACPI_TYPE_ANY, handle, ACPI_UINT32_MAX,
+                                   acpi_bus_check_add, NULL, ops, &device);
 
-               /*
-                * If the device is present, enabled, and functioning then
-                * parse its scope (depth-first).  Note that we need to
-                * represent absent devices to facilitate PnP notifications
-                * -- but only the subtree head (not all of its children,
-                * which will be enumerated when the parent is inserted).
-                *
-                * TBD: Need notifications and other detection mechanisms
-                *      in place before we can fully implement this.
-                */
-                /*
-                * 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)) {
-                               level++;
-                               phandle = chandle;
-                               chandle = NULL;
-                               parent = child;
-                       }
-               }
-       }
+       if (child)
+               *child = device;
 
-       return 0;
+       if (device)
+               return 0;
+       else
+               return -ENODEV;
 }
 
+/*
+ * acpi_bus_add and acpi_bus_start
+ *
+ * scan a given ACPI tree and (probably recently hot-plugged)
+ * create and add or starts found devices.
+ *
+ * If no devices were found -ENODEV is returned which does not
+ * mean that this is a real error, there just have been no suitable
+ * ACPI objects in the table trunk from which the kernel could create
+ * a device and add/start an appropriate driver.
+ */
+
 int
 acpi_bus_add(struct acpi_device **child,
             struct acpi_device *parent, acpi_handle handle, int type)
 {
-       int result;
        struct acpi_bus_ops ops;
 
        memset(&ops, 0, sizeof(ops));
        ops.acpi_op_add = 1;
 
-       result = acpi_add_single_object(child, handle, type, &ops);
-       if (!result)
-               result = acpi_bus_scan(*child, &ops);
-
-       return result;
+       return acpi_bus_scan(handle, &ops, child);
 }
 EXPORT_SYMBOL(acpi_bus_add);
 
 int acpi_bus_start(struct acpi_device *device)
 {
-       int result;
        struct acpi_bus_ops ops;
 
-
        if (!device)
                return -EINVAL;
 
-       result = acpi_start_single_object(device);
-       if (!result) {
-               memset(&ops, 0, sizeof(ops));
-               ops.acpi_op_start = 1;
-               result = acpi_bus_scan(device, &ops);
-       }
-       return result;
+       memset(&ops, 0, sizeof(ops));
+       ops.acpi_op_start = 1;
+
+       return acpi_bus_scan(device->handle, &ops, NULL);
 }
 EXPORT_SYMBOL(acpi_bus_start);
 
@@ -1612,12 +1510,14 @@ static int acpi_bus_scan_fixed(void)
        if ((acpi_gbl_FADT.flags & ACPI_FADT_POWER_BUTTON) == 0) {
                result = acpi_add_single_object(&device, NULL,
                                                ACPI_BUS_TYPE_POWER_BUTTON,
+                                               ACPI_STA_DEFAULT,
                                                &ops);
        }
 
        if ((acpi_gbl_FADT.flags & ACPI_FADT_SLEEP_BUTTON) == 0) {
                result = acpi_add_single_object(&device, NULL,
                                                ACPI_BUS_TYPE_SLEEP_BUTTON,
+                                               ACPI_STA_DEFAULT,
                                                &ops);
        }
 
@@ -1640,24 +1540,15 @@ int __init acpi_scan_init(void)
        }
 
        /*
-        * Create the root device in the bus's device tree
-        */
-       result = acpi_add_single_object(&acpi_root, ACPI_ROOT_OBJECT,
-                                       ACPI_BUS_TYPE_SYSTEM, &ops);
-       if (result)
-               goto Done;
-
-       /*
         * Enumerate devices in the ACPI namespace.
         */
-       result = acpi_bus_scan_fixed();
+       result = acpi_bus_scan(ACPI_ROOT_OBJECT, &ops, &acpi_root);
 
        if (!result)
-               result = acpi_bus_scan(acpi_root, &ops);
+               result = acpi_bus_scan_fixed();
 
        if (result)
                acpi_device_unregister(acpi_root, ACPI_BUS_REMOVAL_NORMAL);
 
-Done:
        return result;
 }