1 files changed, 20 insertions, 17 deletions

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index b23825ecfa37..6155eeb2e89a 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -26,6 +26,8 @@ extern struct acpi_device *acpi_root;
 
 #define ACPI_IS_ROOT_DEVICE(device)    (!(device)->parent)
 
+static const char *dummy_hid = "device";
+
 static LIST_HEAD(acpi_device_list);
 static LIST_HEAD(acpi_bus_id_list);
 DEFINE_MUTEX(acpi_device_lock);
@@ -49,6 +51,9 @@ static int create_modalias(struct acpi_device *acpi_dev, char *modalias,
         int count;
         struct acpi_hardware_id *id;
 
+        if (list_empty(&acpi_dev->pnp.ids))
+                return 0;
+
         len = snprintf(modalias, size, "acpi:");
         size -= len;
 
@@ -202,13 +207,15 @@ static int acpi_device_setup_files(struct acpi_device *dev)
                         goto end;
         }
 
-        result = device_create_file(&dev->dev, &dev_attr_hid);
-        if (result)
-                goto end;
+        if (!list_empty(&dev->pnp.ids)) {
+                result = device_create_file(&dev->dev, &dev_attr_hid);
+                if (result)
+                        goto end;
 
-        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
@@ -316,6 +323,9 @@ static int acpi_device_uevent(struct device *dev, struct kobj_uevent_env *env)
         struct acpi_device *acpi_dev = to_acpi_device(dev);
         int len;
 
+        if (list_empty(&acpi_dev->pnp.ids))
+                return 0;
+
         if (add_uevent_var(env, "MODALIAS="))
                 return -ENOMEM;
         len = create_modalias(acpi_dev, &env->buf[env->buflen - 1],
@@ -1010,10 +1020,13 @@ static int acpi_dock_match(struct acpi_device *device)
         return acpi_get_handle(device->handle, "_DCK", &tmp);
 }
 
-char *acpi_device_hid(struct acpi_device *device)
+const char *acpi_device_hid(struct acpi_device *device)
 {
         struct acpi_hardware_id *hid;
 
+        if (list_empty(&device->pnp.ids))
+                return dummy_hid;
+
         hid = list_first_entry(&device->pnp.ids, struct acpi_hardware_id, list);
         return hid->id;
 }
@@ -1142,16 +1155,6 @@ static void acpi_device_set_id(struct acpi_device *device)
                 acpi_add_id(device, ACPI_BUTTON_HID_SLEEPF);
                 break;
         }
-
-        /*
-         * 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 (list_empty(&device->pnp.ids))
-                acpi_add_id(device, "device");
 }
 
 static int acpi_device_set_context(struct acpi_device *device)