diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index eb30e5ab4cab..b679bf8478f7 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -226,16 +226,6 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
 	struct acpi_memory_info *info;
 	int node;
 
-
-	/* Get the range from the _CRS */
-	result = acpi_memory_get_device_resources(mem_device);
-	if (result) {
-		dev_err(&mem_device->device->dev,
-			"get_device_resources failed\n");
-		mem_device->state = MEMORY_INVALID_STATE;
-		return result;
-	}
-
 	node = acpi_get_node(mem_device->device->handle);
 	/*
 	 * Tell the VM there is more memory here...
@@ -342,14 +332,6 @@ static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
 			break;
 		}
 
-		if (acpi_memory_check_device(mem_device))
-			break;
-
-		if (acpi_memory_enable_device(mem_device)) {
-			acpi_handle_err(handle,"Cannot enable memory device\n");
-			break;
-		}
-
 		ost_code = ACPI_OST_SC_SUCCESS;
 		break;
 
diff --git a/drivers/acpi/apei/erst-dbg.c b/drivers/acpi/apei/erst-dbg.c
index 903549df809b..04ab5c9d3ced 100644
--- a/drivers/acpi/apei/erst-dbg.c
+++ b/drivers/acpi/apei/erst-dbg.c
@@ -111,8 +111,17 @@ static ssize_t erst_dbg_read(struct file *filp, char __user *ubuf,
 	if (rc)
 		goto out;
 	/* no more record */
-	if (id == APEI_ERST_INVALID_RECORD_ID)
+	if (id == APEI_ERST_INVALID_RECORD_ID) {
+		/*
+		 * If the persistent store is empty initially, the function
+		 * 'erst_read' below will return "-ENOENT" value. This causes
+		 * 'retry_next' label is entered again. The returned value
+		 * should be zero indicating the read operation is EOF.
+		 */
+		len = 0;
+
 		goto out;
+	}
 retry:
 	rc = len = erst_read(id, erst_dbg_buf, erst_dbg_buf_len);
 	/* The record may be cleared by others, try read next record */
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index f09dc987cf17..c6ff606c6d5b 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -358,8 +358,7 @@ static struct acpi_device *acpi_dev_pm_get_node(struct device *dev)
 	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);
 	struct acpi_device *adev;
 
-	return handle && ACPI_SUCCESS(acpi_bus_get_device(handle, &adev)) ?
-		adev : NULL;
+	return handle && !acpi_bus_get_device(handle, &adev) ? adev : NULL;
 }
 
 /**
diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
index 01551840d236..95af6f674a6c 100644
--- a/drivers/acpi/glue.c
+++ b/drivers/acpi/glue.c
@@ -18,9 +18,14 @@
 
 #define ACPI_GLUE_DEBUG	0
 #if ACPI_GLUE_DEBUG
-#define DBG(x...) printk(PREFIX x)
+#define DBG(fmt, ...)						\
+	printk(KERN_DEBUG PREFIX fmt, ##__VA_ARGS__)
 #else
-#define DBG(x...) do { } while(0)
+#define DBG(fmt, ...)						\
+do {								\
+	if (0)							\
+		printk(KERN_DEBUG PREFIX fmt, ##__VA_ARGS__);	\
+} while (0)
 #endif
 static LIST_HEAD(bus_type_list);
 static DECLARE_RWSEM(bus_type_sem);
diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c
index 7db61b8fa11f..6e7b9d523812 100644
--- a/drivers/acpi/power.c
+++ b/drivers/acpi/power.c
@@ -445,11 +445,8 @@ int acpi_power_resource_register_device(struct device *dev, acpi_handle handle)
 		return -ENODEV;
 
 	ret = acpi_bus_get_device(handle, &acpi_dev);
-	if (ret)
-		goto no_power_resource;
-
-	if (!acpi_dev->power.flags.power_resources)
-		goto no_power_resource;
+	if (ret || !acpi_dev->power.flags.power_resources)
+		return -ENODEV;
 
 	powered_device = kzalloc(sizeof(*powered_device), GFP_KERNEL);
 	if (!powered_device)
@@ -471,10 +468,6 @@ int acpi_power_resource_register_device(struct device *dev, acpi_handle handle)
 	}
 
 	return ret;
-
-no_power_resource:
-	printk(KERN_DEBUG PREFIX "Invalid Power Resource to register!\n");
-	return -ENODEV;
 }
 EXPORT_SYMBOL_GPL(acpi_power_resource_register_device);
 
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 53502d1bbf26..c88be6c37c30 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -1346,7 +1346,7 @@ static void acpi_device_set_id(struct acpi_device *device)
 			acpi_add_id(device, ACPI_DOCK_HID);
 		else if (!acpi_ibm_smbus_match(device))
 			acpi_add_id(device, ACPI_SMBUS_IBM_HID);
-		else if (!acpi_device_hid(device) &&
+		else if (list_empty(&device->pnp.ids) &&
 			 ACPI_IS_ROOT_DEVICE(device->parent)) {
 			acpi_add_id(device, ACPI_BUS_HID); /* \_SB, LNXSYBUS */
 			strcpy(device->pnp.device_name, ACPI_BUS_DEVICE_NAME);