diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 1a40111e1c86..891c42d1cd65 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -180,14 +180,15 @@ static void acpi_print_osc_error(acpi_handle handle,
 	int i;
 
 	if (ACPI_FAILURE(acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer)))
-		printk(KERN_DEBUG "%s\n", error);
+		printk(KERN_DEBUG "%s: %s\n", context->uuid_str, error);
 	else {
-		printk(KERN_DEBUG "%s:%s\n", (char *)buffer.pointer, error);
+		printk(KERN_DEBUG "%s (%s): %s\n",
+		       (char *)buffer.pointer, context->uuid_str, error);
 		kfree(buffer.pointer);
 	}
-	printk(KERN_DEBUG"_OSC request data:");
+	printk(KERN_DEBUG "_OSC request data:");
 	for (i = 0; i < context->cap.length; i += sizeof(u32))
-		printk("%x ", *((u32 *)(context->cap.pointer + i)));
+		printk(" %x", *((u32 *)(context->cap.pointer + i)));
 	printk("\n");
 }
 
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 11d87bf67e73..1e6833a5cd44 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -86,6 +86,14 @@ bool acpi_scan_is_offline(struct acpi_device *adev, bool uevent);
 #define ACPI_STA_DEFAULT (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED | \
 			  ACPI_STA_DEVICE_UI | ACPI_STA_DEVICE_FUNCTIONING)
 
+extern struct list_head acpi_bus_id_list;
+
+struct acpi_device_bus_id {
+	char bus_id[15];
+	unsigned int instance_no;
+	struct list_head node;
+};
+
 int acpi_device_add(struct acpi_device *device,
 		    void (*release)(struct device *));
 void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index bb66093b7799..67da6fb72274 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -366,6 +366,19 @@ static void acpi_unmap(acpi_physical_address pg_off, void __iomem *vaddr)
 		iounmap(vaddr);
 }
 
+/**
+ * acpi_os_map_iomem - Get a virtual address for a given physical address range.
+ * @phys: Start of the physical address range to map.
+ * @size: Size of the physical address range to map.
+ *
+ * Look up the given physical address range in the list of existing ACPI memory
+ * mappings.  If found, get a reference to it and return a pointer to it (its
+ * virtual address).  If not found, map it, add it to that list and return a
+ * pointer to it.
+ *
+ * During early init (when acpi_gbl_permanent_mmap has not been set yet) this
+ * routine simply calls __acpi_map_table() to get the job done.
+ */
 void __iomem *__init_refok
 acpi_os_map_iomem(acpi_physical_address phys, acpi_size size)
 {
@@ -441,6 +454,20 @@ static void acpi_os_map_cleanup(struct acpi_ioremap *map)
 	}
 }
 
+/**
+ * acpi_os_unmap_iomem - Drop a memory mapping reference.
+ * @virt: Start of the address range to drop a reference to.
+ * @size: Size of the address range to drop a reference to.
+ *
+ * Look up the given virtual address range in the list of existing ACPI memory
+ * mappings, drop a reference to it and unmap it if there are no more active
+ * references to it.
+ *
+ * During early init (when acpi_gbl_permanent_mmap has not been set yet) this
+ * routine simply calls __acpi_unmap_table() to get the job done.  Since
+ * __acpi_unmap_table() is an __init function, the __ref annotation is needed
+ * here.
+ */
 void __ref acpi_os_unmap_iomem(void __iomem *virt, acpi_size size)
 {
 	struct acpi_ioremap *map;
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 78d5f02a073b..407a3760e8de 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -39,7 +39,7 @@ static const char *dummy_hid = "device";
 
 static LIST_HEAD(acpi_dep_list);
 static DEFINE_MUTEX(acpi_dep_list_lock);
-static LIST_HEAD(acpi_bus_id_list);
+LIST_HEAD(acpi_bus_id_list);
 static DEFINE_MUTEX(acpi_scan_lock);
 static LIST_HEAD(acpi_scan_handlers_list);
 DEFINE_MUTEX(acpi_device_lock);
@@ -52,12 +52,6 @@ struct acpi_dep_data {
 	acpi_handle slave;
 };
 
-struct acpi_device_bus_id{
-	char bus_id[15];
-	unsigned int instance_no;
-	struct list_head node;
-};
-
 void acpi_scan_lock_acquire(void)
 {
 	mutex_lock(&acpi_scan_lock);
@@ -471,10 +465,24 @@ static void acpi_device_release(struct device *dev)
 
 static void acpi_device_del(struct acpi_device *device)
 {
+	struct acpi_device_bus_id *acpi_device_bus_id;
+
 	mutex_lock(&acpi_device_lock);
 	if (device->parent)
 		list_del(&device->node);
 
+	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
+		if (!strcmp(acpi_device_bus_id->bus_id,
+			    acpi_device_hid(device))) {
+			if (acpi_device_bus_id->instance_no > 0)
+				acpi_device_bus_id->instance_no--;
+			else {
+				list_del(&acpi_device_bus_id->node);
+				kfree(acpi_device_bus_id);
+			}
+			break;
+		}
+
 	list_del(&device->wakeup_list);
 	mutex_unlock(&acpi_device_lock);
 
@@ -1461,7 +1469,7 @@ static int acpi_bus_type_and_status(acpi_handle handle, int *type,
 		*type = ACPI_BUS_TYPE_DEVICE;
 		status = acpi_bus_get_status_handle(handle, sta);
 		if (ACPI_FAILURE(status))
-			return -ENODEV;
+			*sta = 0;
 		break;
 	case ACPI_TYPE_PROCESSOR:
 		*type = ACPI_BUS_TYPE_PROCESSOR;
diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c
index 475c9079bf85..f2f9873bb5c3 100644
--- a/drivers/acpi/utils.c
+++ b/drivers/acpi/utils.c
@@ -29,6 +29,7 @@
 #include <linux/dynamic_debug.h>
 
 #include "internal.h"
+#include "sleep.h"
 
 #define _COMPONENT		ACPI_BUS_COMPONENT
 ACPI_MODULE_NAME("utils");
@@ -709,6 +710,36 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, int rev, u64 funcs)
 }
 EXPORT_SYMBOL(acpi_check_dsm);
 
+/**
+ * acpi_dev_present - Detect presence of a given ACPI device in the system.
+ * @hid: Hardware ID of the device.
+ *
+ * Return %true if the device was present at the moment of invocation.
+ * Note that if the device is pluggable, it may since have disappeared.
+ *
+ * For this function to work, acpi_bus_scan() must have been executed
+ * which happens in the subsys_initcall() subsection. Hence, do not
+ * call from a subsys_initcall() or earlier (use acpi_get_devices()
+ * instead). Calling from module_init() is fine (which is synonymous
+ * with device_initcall()).
+ */
+bool acpi_dev_present(const char *hid)
+{
+	struct acpi_device_bus_id *acpi_device_bus_id;
+	bool found = false;
+
+	mutex_lock(&acpi_device_lock);
+	list_for_each_entry(acpi_device_bus_id, &acpi_bus_id_list, node)
+		if (!strcmp(acpi_device_bus_id->bus_id, hid)) {
+			found = true;
+			break;
+		}
+	mutex_unlock(&acpi_device_lock);
+
+	return found;
+}
+EXPORT_SYMBOL(acpi_dev_present);
+
 /*
  * acpi_backlight= handling, this is done here rather then in video_detect.c
  * because __setup cannot be used in modules.
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index ad0a5ff3d4cd..14362a84c78e 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -87,6 +87,8 @@ acpi_evaluate_dsm_typed(acpi_handle handle, const u8 *uuid, int rev, int func,
 	  .package.elements = (eles)			\
 	}
 
+bool acpi_dev_present(const char *hid);
+
 #ifdef CONFIG_ACPI
 
 #include <linux/proc_fs.h>
@@ -631,7 +633,9 @@ static inline bool acpi_device_can_wakeup(struct acpi_device *adev)
 
 static inline bool acpi_device_can_poweroff(struct acpi_device *adev)
 {
-	return adev->power.states[ACPI_STATE_D3_COLD].flags.valid;
+	return adev->power.states[ACPI_STATE_D3_COLD].flags.valid ||
+		((acpi_gbl_FADT.header.revision < 6) &&
+		adev->power.states[ACPI_STATE_D3_HOT].flags.explicit_set);
 }
 
 #else	/* CONFIG_ACPI */