Merge branches 'pm-qos', 'pm-domains' and 'pm-drivers'

* pm-qos:
PM / QoS: Add type to dev_pm_qos_add_ancestor_request() arguments
ACPI / LPSS: Support for device latency tolerance PM QoS
ACPI / scan: Add bind/unbind callbacks to struct acpi_scan_handler
PM / QoS: Introcuce latency tolerance device PM QoS type
PM / QoS: Add no_constraints_value field to struct pm_qos_constraints
PM / QoS: Rename device resume latency QoS items

* pm-domains:
PM / domains: Turn latency warning into debug message

* pm-drivers:
PM: Add pm_runtime_suspend|resume_force functions
PM / runtime: Fetch runtime PM callbacks using a macro

Documentation/ABI/testing/sysfs-devices-power

···
 		Not all drivers support this attribute.  If it isn't supported,
 		attempts to read or write it will yield I/O errors.
 
-What:		/sys/devices/.../power/pm_qos_latency_us
+What:		/sys/devices/.../power/pm_qos_resume_latency_us
 Date:		March 2012
 Contact:	Rafael J. Wysocki <[e-mail]>
 Description:
···
 
 		This attribute has no effect on system-wide suspend/resume and
 		hibernation.
+
+What:		/sys/devices/.../power/pm_qos_latency_tolerance_us
+Date:		January 2014
+Contact:	Rafael J. Wysocki <[e-mail]>
+Description:
+		The /sys/devices/.../power/pm_qos_latency_tolerance_us attribute
+		contains the PM QoS active state latency tolerance limit for the
+		given device in microseconds.  That is the maximum memory access
+		latency the device can suffer without any visible adverse
+		effects on user space functionality.  If that value is the
+		string "any", the latency does not matter to user space at all,
+		but hardware should not be allowed to set the latency tolerance
+		for the device automatically.
+
+		Reading "auto" from this file means that the maximum memory
+		access latency for the device may be determined automatically
+		by the hardware as needed.  Writing "auto" to it allows the
+		hardware to be switched to this mode if there are no other
+		latency tolerance requirements from the kernel side.
+
+		This attribute is only present if the feature controlled by it
+		is supported by the hardware.
+
+		This attribute has no effect on runtime suspend and resume of
+		devices and on system-wide suspend/resume and hibernation.
 
 What:		/sys/devices/.../power/pm_qos_no_power_off
 Date:		September 2012

Documentation/power/pm_qos_interface.txt

···
 
 2. PM QoS per-device latency and flags framework
 
-For each device, there are two lists of PM QoS requests. One is maintained
-along with the aggregated target of latency value and the other is for PM QoS
-flags. Values are updated in response to changes of the request list.
+For each device, there are three lists of PM QoS requests. Two of them are
+maintained along with the aggregated targets of resume latency and active
+state latency tolerance (in microseconds) and the third one is for PM QoS flags.
+Values are updated in response to changes of the request list.
 
-Target latency value is simply the minimum of the request values held in the
-parameter list elements.  The PM QoS flags aggregate value is a gather (bitwise
-OR) of all list elements' values. Two device PM QoS flags are defined currently:
-PM_QOS_FLAG_NO_POWER_OFF and PM_QOS_FLAG_REMOTE_WAKEUP.
+The target values of resume latency and active state latency tolerance are
+simply the minimum of the request values held in the parameter list elements.
+The PM QoS flags aggregate value is a gather (bitwise OR) of all list elements'
+values.  Two device PM QoS flags are defined currently: PM_QOS_FLAG_NO_POWER_OFF
+and PM_QOS_FLAG_REMOTE_WAKEUP.
 
-Note: the aggregated target value is implemented as an atomic variable so that
-reading the aggregated value does not require any locking mechanism.
+Note: The aggregated target values are implemented in such a way that reading
+the aggregated value does not require any locking mechanism.
 
 
 From kernel mode the use of this interface is the following:
···
 	PM_QOS_FLAGS_UNDEFINED: The device's PM QoS structure has not been
 			initialized or the list of requests is empty.
 
-int dev_pm_qos_add_ancestor_request(dev, handle, value)
+int dev_pm_qos_add_ancestor_request(dev, handle, type, value)
 Add a PM QoS request for the first direct ancestor of the given device whose
-power.ignore_children flag is unset.
+power.ignore_children flag is unset (for DEV_PM_QOS_RESUME_LATENCY requests)
+or whose power.set_latency_tolerance callback pointer is not NULL (for
+DEV_PM_QOS_LATENCY_TOLERANCE requests).
 
 int dev_pm_qos_expose_latency_limit(device, value)
-Add a request to the device's PM QoS list of latency constraints and create
-a sysfs attribute pm_qos_resume_latency_us under the device's power directory
-allowing user space to manipulate that request.
+Add a request to the device's PM QoS list of resume latency constraints and
+create a sysfs attribute pm_qos_resume_latency_us under the device's power
+directory allowing user space to manipulate that request.
 
 void dev_pm_qos_hide_latency_limit(device)
 Drop the request added by dev_pm_qos_expose_latency_limit() from the device's
-PM QoS list of latency constraints and remove sysfs attribute pm_qos_resume_latency_us
-from the device's power directory.
+PM QoS list of resume latency constraints and remove sysfs attribute
+pm_qos_resume_latency_us from the device's power directory.
 
 int dev_pm_qos_expose_flags(device, value)
 Add a request to the device's PM QoS list of flags and create sysfs attributes
···
 int dev_pm_qos_add_notifier(device, notifier):
 Adds a notification callback function for the device.
 The callback is called when the aggregated value of the device constraints list
-is changed.
+is changed (for resume latency device PM QoS only).
 
 int dev_pm_qos_remove_notifier(device, notifier):
 Removes the notification callback function for the device.
···
 int dev_pm_qos_add_global_notifier(notifier):
 Adds a notification callback function in the global notification tree of the
 framework.
-The callback is called when the aggregated value for any device is changed.
+The callback is called when the aggregated value for any device is changed
+(for resume latency device PM QoS only).
 
 int dev_pm_qos_remove_global_notifier(notifier):
 Removes the notification callback function from the global notification tree
 of the framework.
 
 
-From user mode:
-No API for user space access to the per-device latency constraints is provided
-yet - still under discussion.
+Active state latency tolerance
 
+This device PM QoS type is used to support systems in which hardware may switch
+to energy-saving operation modes on the fly.  In those systems, if the operation
+mode chosen by the hardware attempts to save energy in an overly aggressive way,
+it may cause excess latencies to be visible to software, causing it to miss
+certain protocol requirements or target frame or sample rates etc.
+
+If there is a latency tolerance control mechanism for a given device available
+to software, the .set_latency_tolerance callback in that device's dev_pm_info
+structure should be populated.  The routine pointed to by it is should implement
+whatever is necessary to transfer the effective requirement value to the
+hardware.
+
+Whenever the effective latency tolerance changes for the device, its
+.set_latency_tolerance() callback will be executed and the effective value will
+be passed to it.  If that value is negative, which means that the list of
+latency tolerance requirements for the device is empty, the callback is expected
+to switch the underlying hardware latency tolerance control mechanism to an
+autonomous mode if available.  If that value is PM_QOS_LATENCY_ANY, in turn, and
+the hardware supports a special "no requirement" setting, the callback is
+expected to use it.  That allows software to prevent the hardware from
+automatically updating the device's latency tolerance in response to its power
+state changes (e.g. during transitions from D3cold to D0), which generally may
+be done in the autonomous latency tolerance control mode.
+
+If .set_latency_tolerance() is present for the device, sysfs attribute
+pm_qos_latency_tolerance_us will be present in the devivce's power directory.
+Then, user space can use that attribute to specify its latency tolerance
+requirement for the device, if any.  Writing "any" to it means "no requirement,
+but do not let the hardware control latency tolerance" and writing "auto" to it
+allows the hardware to be switched to the autonomous mode if there are no other
+requirements from the kernel side in the device's list.
+
+Kernel code can use the functions described above along with the
+DEV_PM_QOS_LATENCY_TOLERANCE device PM QoS type to add, remove and update
+latency tolerance requirements for devices.

Documentation/trace/events-power.txt

···
 
 The first parameter gives the device name which tries to add/update/remove
 QoS requests.
-The second parameter gives the request type (e.g. "DEV_PM_QOS_LATENCY").
+The second parameter gives the request type (e.g. "DEV_PM_QOS_RESUME_LATENCY").
 The third parameter is value to be added/updated/removed.

drivers/acpi/acpi_lpss.c

···
 #define LPSS_GENERAL_UART_RTS_OVRD	BIT(3)
 #define LPSS_SW_LTR			0x10
 #define LPSS_AUTO_LTR			0x14
+#define LPSS_LTR_SNOOP_REQ		BIT(15)
+#define LPSS_LTR_SNOOP_MASK		0x0000FFFF
+#define LPSS_LTR_SNOOP_LAT_1US		0x800
+#define LPSS_LTR_SNOOP_LAT_32US		0xC00
+#define LPSS_LTR_SNOOP_LAT_SHIFT	5
+#define LPSS_LTR_SNOOP_LAT_CUTOFF	3000
+#define LPSS_LTR_MAX_VAL		0x3FF
 #define LPSS_TX_INT			0x20
 #define LPSS_TX_INT_MASK		BIT(1)
 
···
 	return ret;
 }
 
+static u32 __lpss_reg_read(struct lpss_private_data *pdata, unsigned int reg)
+{
+	return readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
+static void __lpss_reg_write(u32 val, struct lpss_private_data *pdata,
+			     unsigned int reg)
+{
+	writel(val, pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+}
+
 static int lpss_reg_read(struct device *dev, unsigned int reg, u32 *val)
 {
 	struct acpi_device *adev;
···
 		ret = -ENODEV;
 		goto out;
 	}
-	*val = readl(pdata->mmio_base + pdata->dev_desc->prv_offset + reg);
+	*val = __lpss_reg_read(pdata, reg);
 
  out:
 	spin_unlock_irqrestore(&dev->power.lock, flags);
···
 	.name = "lpss_ltr",
 };
 
+static void acpi_lpss_set_ltr(struct device *dev, s32 val)
+{
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+	u32 ltr_mode, ltr_val;
+
+	ltr_mode = __lpss_reg_read(pdata, LPSS_GENERAL);
+	if (val < 0) {
+		if (ltr_mode & LPSS_GENERAL_LTR_MODE_SW) {
+			ltr_mode &= ~LPSS_GENERAL_LTR_MODE_SW;
+			__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+		}
+		return;
+	}
+	ltr_val = __lpss_reg_read(pdata, LPSS_SW_LTR) & ~LPSS_LTR_SNOOP_MASK;
+	if (val >= LPSS_LTR_SNOOP_LAT_CUTOFF) {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_32US;
+		val = LPSS_LTR_MAX_VAL;
+	} else if (val > LPSS_LTR_MAX_VAL) {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_32US | LPSS_LTR_SNOOP_REQ;
+		val >>= LPSS_LTR_SNOOP_LAT_SHIFT;
+	} else {
+		ltr_val |= LPSS_LTR_SNOOP_LAT_1US | LPSS_LTR_SNOOP_REQ;
+	}
+	ltr_val |= val;
+	__lpss_reg_write(ltr_val, pdata, LPSS_SW_LTR);
+	if (!(ltr_mode & LPSS_GENERAL_LTR_MODE_SW)) {
+		ltr_mode |= LPSS_GENERAL_LTR_MODE_SW;
+		__lpss_reg_write(ltr_mode, pdata, LPSS_GENERAL);
+	}
+}
+
 static int acpi_lpss_platform_notify(struct notifier_block *nb,
 				     unsigned long action, void *data)
 {
···
 	.notifier_call = acpi_lpss_platform_notify,
 };
 
+static void acpi_lpss_bind(struct device *dev)
+{
+	struct lpss_private_data *pdata = acpi_driver_data(ACPI_COMPANION(dev));
+
+	if (!pdata || !pdata->mmio_base || !pdata->dev_desc->ltr_required)
+		return;
+
+	if (pdata->mmio_size >= pdata->dev_desc->prv_offset + LPSS_LTR_SIZE)
+		dev->power.set_latency_tolerance = acpi_lpss_set_ltr;
+	else
+		dev_err(dev, "MMIO size insufficient to access LTR\n");
+}
+
+static void acpi_lpss_unbind(struct device *dev)
+{
+	dev->power.set_latency_tolerance = NULL;
+}
+
 static struct acpi_scan_handler lpss_handler = {
 	.ids = acpi_lpss_device_ids,
 	.attach = acpi_lpss_create_device,
+	.bind = acpi_lpss_bind,
+	.unbind = acpi_lpss_unbind,
 };
 
 void __init acpi_lpss_init(void)

drivers/acpi/glue.c

···
 static int acpi_platform_notify(struct device *dev)
 {
 	struct acpi_bus_type *type = acpi_get_bus_type(dev);
+	struct acpi_device *adev;
 	int ret;
 
 	ret = acpi_bind_one(dev, NULL);
···
 		if (ret)
 			goto out;
 	}
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		goto out;
 
 	if (type && type->setup)
 		type->setup(dev);
+	else if (adev->handler && adev->handler->bind)
+		adev->handler->bind(dev);
 
  out:
 #if ACPI_GLUE_DEBUG
···
 
 static int acpi_platform_notify_remove(struct device *dev)
 {
+	struct acpi_device *adev = ACPI_COMPANION(dev);
 	struct acpi_bus_type *type;
+
+	if (!adev)
+		return 0;
 
 	type = acpi_get_bus_type(dev);
 	if (type && type->cleanup)
 		type->cleanup(dev);
+	else if (adev->handler && adev->handler->unbind)
+		adev->handler->unbind(dev);
 
 	acpi_unbind_one(dev);
 	return 0;

drivers/acpi/scan.c

···
 
 		handler = acpi_scan_match_handler(hwid->id, &devid);
 		if (handler) {
+			device->handler = handler;
 			ret = handler->attach(device, devid);
-			if (ret > 0) {
-				device->handler = handler;
+			if (ret > 0)
 				break;
-			} else if (ret < 0) {
+
+			device->handler = NULL;
+			if (ret < 0)
 				break;
-			}
 		}
 	}
 	return ret;

drivers/base/power/Makefile

···
-obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o qos.o
+obj-$(CONFIG_PM)	+= sysfs.o generic_ops.o common.o qos.o runtime.o
 obj-$(CONFIG_PM_SLEEP)	+= main.o wakeup.o
-obj-$(CONFIG_PM_RUNTIME)	+= runtime.o
 obj-$(CONFIG_PM_TRACE_RTC)	+= trace.o
 obj-$(CONFIG_PM_OPP)	+= opp.o
 obj-$(CONFIG_PM_GENERIC_DOMAINS)	+=  domain.o domain_governor.o

drivers/base/power/domain.c

···
 	struct gpd_timing_data *__td = &dev_gpd_data(dev)->td;			\
 	if (!__retval && __elapsed > __td->field) {				\
 		__td->field = __elapsed;					\
-		dev_warn(dev, name " latency exceeded, new value %lld ns\n",	\
+		dev_dbg(dev, name " latency exceeded, new value %lld ns\n",	\
 			__elapsed);						\
 		genpd->max_off_time_changed = true;				\
 		__td->constraint_changed = true;				\

drivers/base/power/power.h

···
 extern void rpm_sysfs_remove(struct device *dev);
 extern int wakeup_sysfs_add(struct device *dev);
 extern void wakeup_sysfs_remove(struct device *dev);
-extern int pm_qos_sysfs_add_latency(struct device *dev);
-extern void pm_qos_sysfs_remove_latency(struct device *dev);
+extern int pm_qos_sysfs_add_resume_latency(struct device *dev);
+extern void pm_qos_sysfs_remove_resume_latency(struct device *dev);
 extern int pm_qos_sysfs_add_flags(struct device *dev);
 extern void pm_qos_sysfs_remove_flags(struct device *dev);
 

drivers/base/power/qos.c

···
 s32 __dev_pm_qos_read_value(struct device *dev)
 {
 	return IS_ERR_OR_NULL(dev->power.qos) ?
-		0 : pm_qos_read_value(&dev->power.qos->latency);
+		0 : pm_qos_read_value(&dev->power.qos->resume_latency);
 }
 
 /**
···
 	int ret;
 
 	switch(req->type) {
-	case DEV_PM_QOS_LATENCY:
-		ret = pm_qos_update_target(&qos->latency, &req->data.pnode,
-					   action, value);
+	case DEV_PM_QOS_RESUME_LATENCY:
+		ret = pm_qos_update_target(&qos->resume_latency,
+					   &req->data.pnode, action, value);
 		if (ret) {
-			value = pm_qos_read_value(&qos->latency);
+			value = pm_qos_read_value(&qos->resume_latency);
 			blocking_notifier_call_chain(&dev_pm_notifiers,
 						     (unsigned long)value,
 						     req);
+		}
+		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		ret = pm_qos_update_target(&qos->latency_tolerance,
+					   &req->data.pnode, action, value);
+		if (ret) {
+			value = pm_qos_read_value(&qos->latency_tolerance);
+			req->dev->power.set_latency_tolerance(req->dev, value);
 		}
 		break;
 	case DEV_PM_QOS_FLAGS:
···
 	}
 	BLOCKING_INIT_NOTIFIER_HEAD(n);
 
-	c = &qos->latency;
+	c = &qos->resume_latency;
 	plist_head_init(&c->list);
-	c->target_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
-	c->default_value = PM_QOS_DEV_LAT_DEFAULT_VALUE;
+	c->target_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
+	c->default_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_RESUME_LATENCY_DEFAULT_VALUE;
 	c->type = PM_QOS_MIN;
 	c->notifiers = n;
+
+	c = &qos->latency_tolerance;
+	plist_head_init(&c->list);
+	c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
+	c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE;
+	c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
+	c->type = PM_QOS_MIN;
 
 	INIT_LIST_HEAD(&qos->flags.list);
 
···
 	 * If the device's PM QoS resume latency limit or PM QoS flags have been
 	 * exposed to user space, they have to be hidden at this point.
 	 */
-	pm_qos_sysfs_remove_latency(dev);
+	pm_qos_sysfs_remove_resume_latency(dev);
 	pm_qos_sysfs_remove_flags(dev);
 
 	mutex_lock(&dev_pm_qos_mtx);
···
 		goto out;
 
 	/* Flush the constraints lists for the device. */
-	c = &qos->latency;
+	c = &qos->resume_latency;
 	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 		/*
 		 * Update constraints list and call the notification
 		 * callbacks if needed
 		 */
+		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+		memset(req, 0, sizeof(*req));
+	}
+	c = &qos->latency_tolerance;
+	plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) {
 		apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
 		memset(req, 0, sizeof(*req));
 	}
···
 	mutex_unlock(&dev_pm_qos_mtx);
 
 	mutex_unlock(&dev_pm_qos_sysfs_mtx);
+}
+
+static bool dev_pm_qos_invalid_request(struct device *dev,
+				       struct dev_pm_qos_request *req)
+{
+	return !req || (req->type == DEV_PM_QOS_LATENCY_TOLERANCE
+			&& !dev->power.set_latency_tolerance);
+}
+
+static int __dev_pm_qos_add_request(struct device *dev,
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value)
+{
+	int ret = 0;
+
+	if (!dev || dev_pm_qos_invalid_request(dev, req))
+		return -EINVAL;
+
+	if (WARN(dev_pm_qos_request_active(req),
+		 "%s() called for already added request\n", __func__))
+		return -EINVAL;
+
+	if (IS_ERR(dev->power.qos))
+		ret = -ENODEV;
+	else if (!dev->power.qos)
+		ret = dev_pm_qos_constraints_allocate(dev);
+
+	trace_dev_pm_qos_add_request(dev_name(dev), type, value);
+	if (!ret) {
+		req->dev = dev;
+		req->type = type;
+		ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
+	}
+	return ret;
 }
 
 /**
···
 int dev_pm_qos_add_request(struct device *dev, struct dev_pm_qos_request *req,
 			   enum dev_pm_qos_req_type type, s32 value)
 {
-	int ret = 0;
-
-	if (!dev || !req) /*guard against callers passing in null */
-		return -EINVAL;
-
-	if (WARN(dev_pm_qos_request_active(req),
-		 "%s() called for already added request\n", __func__))
-		return -EINVAL;
+	int ret;
 
 	mutex_lock(&dev_pm_qos_mtx);
-
-	if (IS_ERR(dev->power.qos))
-		ret = -ENODEV;
-	else if (!dev->power.qos)
-		ret = dev_pm_qos_constraints_allocate(dev);
-
-	trace_dev_pm_qos_add_request(dev_name(dev), type, value);
-	if (!ret) {
-		req->dev = dev;
-		req->type = type;
-		ret = apply_constraint(req, PM_QOS_ADD_REQ, value);
-	}
-
+	ret = __dev_pm_qos_add_request(dev, req, type, value);
 	mutex_unlock(&dev_pm_qos_mtx);
-
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
···
 		return -ENODEV;
 
 	switch(req->type) {
-	case DEV_PM_QOS_LATENCY:
+	case DEV_PM_QOS_RESUME_LATENCY:
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
 		curr_value = req->data.pnode.prio;
 		break;
 	case DEV_PM_QOS_FLAGS:
···
 		ret = dev_pm_qos_constraints_allocate(dev);
 
 	if (!ret)
-		ret = blocking_notifier_chain_register(
-				dev->power.qos->latency.notifiers, notifier);
+		ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers,
+						       notifier);
 
 	mutex_unlock(&dev_pm_qos_mtx);
 	return ret;
···
 
 	/* Silently return if the constraints object is not present. */
 	if (!IS_ERR_OR_NULL(dev->power.qos))
-		retval = blocking_notifier_chain_unregister(
-				dev->power.qos->latency.notifiers,
-				notifier);
+		retval = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers,
+							    notifier);
 
 	mutex_unlock(&dev_pm_qos_mtx);
 	return retval;
···
  * dev_pm_qos_add_ancestor_request - Add PM QoS request for device's ancestor.
  * @dev: Device whose ancestor to add the request for.
  * @req: Pointer to the preallocated handle.
+ * @type: Type of the request.
  * @value: Constraint latency value.
  */
 int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value)
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value)
 {
 	struct device *ancestor = dev->parent;
 	int ret = -ENODEV;
 
-	while (ancestor && !ancestor->power.ignore_children)
-		ancestor = ancestor->parent;
+	switch (type) {
+	case DEV_PM_QOS_RESUME_LATENCY:
+		while (ancestor && !ancestor->power.ignore_children)
+			ancestor = ancestor->parent;
 
+		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		while (ancestor && !ancestor->power.set_latency_tolerance)
+			ancestor = ancestor->parent;
+
+		break;
+	default:
+		ancestor = NULL;
+	}
 	if (ancestor)
-		ret = dev_pm_qos_add_request(ancestor, req,
-					     DEV_PM_QOS_LATENCY, value);
+		ret = dev_pm_qos_add_request(ancestor, req, type, value);
 
 	if (ret < 0)
 		req->dev = NULL;
···
 	struct dev_pm_qos_request *req = NULL;
 
 	switch(type) {
-	case DEV_PM_QOS_LATENCY:
-		req = dev->power.qos->latency_req;
-		dev->power.qos->latency_req = NULL;
+	case DEV_PM_QOS_RESUME_LATENCY:
+		req = dev->power.qos->resume_latency_req;
+		dev->power.qos->resume_latency_req = NULL;
+		break;
+	case DEV_PM_QOS_LATENCY_TOLERANCE:
+		req = dev->power.qos->latency_tolerance_req;
+		dev->power.qos->latency_tolerance_req = NULL;
 		break;
 	case DEV_PM_QOS_FLAGS:
 		req = dev->power.qos->flags_req;
···
 	if (!req)
 		return -ENOMEM;
 
-	ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY, value);
+	ret = dev_pm_qos_add_request(dev, req, DEV_PM_QOS_RESUME_LATENCY, value);
 	if (ret < 0) {
 		kfree(req);
 		return ret;
···
 
 	if (IS_ERR_OR_NULL(dev->power.qos))
 		ret = -ENODEV;
-	else if (dev->power.qos->latency_req)
+	else if (dev->power.qos->resume_latency_req)
 		ret = -EEXIST;
 
 	if (ret < 0) {
···
 		mutex_unlock(&dev_pm_qos_mtx);
 		goto out;
 	}
-	dev->power.qos->latency_req = req;
+	dev->power.qos->resume_latency_req = req;
 
 	mutex_unlock(&dev_pm_qos_mtx);
 
-	ret = pm_qos_sysfs_add_latency(dev);
+	ret = pm_qos_sysfs_add_resume_latency(dev);
 	if (ret)
-		dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
+		dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
 
  out:
 	mutex_unlock(&dev_pm_qos_sysfs_mtx);
···
 
 static void __dev_pm_qos_hide_latency_limit(struct device *dev)
 {
-	if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->latency_req)
-		__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY);
+	if (!IS_ERR_OR_NULL(dev->power.qos) && dev->power.qos->resume_latency_req)
+		__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_RESUME_LATENCY);
 }
 
 /**
···
 {
 	mutex_lock(&dev_pm_qos_sysfs_mtx);
 
-	pm_qos_sysfs_remove_latency(dev);
+	pm_qos_sysfs_remove_resume_latency(dev);
 
 	mutex_lock(&dev_pm_qos_mtx);
 	__dev_pm_qos_hide_latency_limit(dev);
···
  out:
 	mutex_unlock(&dev_pm_qos_mtx);
 	pm_runtime_put(dev);
+	return ret;
+}
+
+/**
+ * dev_pm_qos_get_user_latency_tolerance - Get user space latency tolerance.
+ * @dev: Device to obtain the user space latency tolerance for.
+ */
+s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
+{
+	s32 ret;
+
+	mutex_lock(&dev_pm_qos_mtx);
+	ret = IS_ERR_OR_NULL(dev->power.qos)
+		|| !dev->power.qos->latency_tolerance_req ?
+			PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT :
+			dev->power.qos->latency_tolerance_req->data.pnode.prio;
+	mutex_unlock(&dev_pm_qos_mtx);
+	return ret;
+}
+
+/**
+ * dev_pm_qos_update_user_latency_tolerance - Update user space latency tolerance.
+ * @dev: Device to update the user space latency tolerance for.
+ * @val: New user space latency tolerance for @dev (negative values disable).
+ */
+int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
+{
+	int ret;
+
+	mutex_lock(&dev_pm_qos_mtx);
+
+	if (IS_ERR_OR_NULL(dev->power.qos)
+	    || !dev->power.qos->latency_tolerance_req) {
+		struct dev_pm_qos_request *req;
+
+		if (val < 0) {
+			ret = -EINVAL;
+			goto out;
+		}
+		req = kzalloc(sizeof(*req), GFP_KERNEL);
+		if (!req) {
+			ret = -ENOMEM;
+			goto out;
+		}
+		ret = __dev_pm_qos_add_request(dev, req, DEV_PM_QOS_LATENCY_TOLERANCE, val);
+		if (ret < 0) {
+			kfree(req);
+			goto out;
+		}
+		dev->power.qos->latency_tolerance_req = req;
+	} else {
+		if (val < 0) {
+			__dev_pm_qos_drop_user_request(dev, DEV_PM_QOS_LATENCY_TOLERANCE);
+			ret = 0;
+		} else {
+			ret = __dev_pm_qos_update_request(dev->power.qos->latency_tolerance_req, val);
+		}
+	}
+
+ out:
+	mutex_unlock(&dev_pm_qos_mtx);
 	return ret;
 }
 #else /* !CONFIG_PM_RUNTIME */

drivers/base/power/runtime.c

···
 #include <trace/events/rpm.h>
 #include "power.h"
 
+#define RPM_GET_CALLBACK(dev, cb)				\
+({								\
+	int (*__rpm_cb)(struct device *__d);			\
+								\
+	if (dev->pm_domain)					\
+		__rpm_cb = dev->pm_domain->ops.cb;		\
+	else if (dev->type && dev->type->pm)			\
+		__rpm_cb = dev->type->pm->cb;			\
+	else if (dev->class && dev->class->pm)			\
+		__rpm_cb = dev->class->pm->cb;			\
+	else if (dev->bus && dev->bus->pm)			\
+		__rpm_cb = dev->bus->pm->cb;			\
+	else							\
+		__rpm_cb = NULL;				\
+								\
+	if (!__rpm_cb && dev->driver && dev->driver->pm)	\
+		__rpm_cb = dev->driver->pm->cb;			\
+								\
+	__rpm_cb;						\
+})
+
+static int (*rpm_get_suspend_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_suspend);
+}
+
+static int (*rpm_get_resume_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_resume);
+}
+
+#ifdef CONFIG_PM_RUNTIME
+static int (*rpm_get_idle_cb(struct device *dev))(struct device *)
+{
+	return RPM_GET_CALLBACK(dev, runtime_idle);
+}
+
 static int rpm_resume(struct device *dev, int rpmflags);
 static int rpm_suspend(struct device *dev, int rpmflags);
 
···
 
 	dev->power.idle_notification = true;
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_idle;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_idle;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_idle;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_idle;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_idle;
+	callback = rpm_get_idle_cb(dev);
 
 	if (callback)
 		retval = __rpm_callback(callback, dev);
···
 
 	__update_runtime_status(dev, RPM_SUSPENDING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_suspend;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_suspend;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_suspend;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_suspend;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_suspend;
+	callback = rpm_get_suspend_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval)
···
 
 	__update_runtime_status(dev, RPM_RESUMING);
 
-	if (dev->pm_domain)
-		callback = dev->pm_domain->ops.runtime_resume;
-	else if (dev->type && dev->type->pm)
-		callback = dev->type->pm->runtime_resume;
-	else if (dev->class && dev->class->pm)
-		callback = dev->class->pm->runtime_resume;
-	else if (dev->bus && dev->bus->pm)
-		callback = dev->bus->pm->runtime_resume;
-	else
-		callback = NULL;
-
-	if (!callback && dev->driver && dev->driver->pm)
-		callback = dev->driver->pm->runtime_resume;
+	callback = rpm_get_resume_cb(dev);
 
 	retval = rpm_callback(callback, dev);
 	if (retval) {
···
 	if (dev->power.irq_safe && dev->parent)
 		pm_runtime_put(dev->parent);
 }
+#endif
+
+/**
+ * pm_runtime_force_suspend - Force a device into suspend state if needed.
+ * @dev: Device to suspend.
+ *
+ * Disable runtime PM so we safely can check the device's runtime PM status and
+ * if it is active, invoke it's .runtime_suspend callback to bring it into
+ * suspend state. Keep runtime PM disabled to preserve the state unless we
+ * encounter errors.
+ *
+ * Typically this function may be invoked from a system suspend callback to make
+ * sure the device is put into low power state.
+ */
+int pm_runtime_force_suspend(struct device *dev)
+{
+	int (*callback)(struct device *);
+	int ret = 0;
+
+	pm_runtime_disable(dev);
+
+	/*
+	 * Note that pm_runtime_status_suspended() returns false while
+	 * !CONFIG_PM_RUNTIME, which means the device will be put into low
+	 * power state.
+	 */
+	if (pm_runtime_status_suspended(dev))
+		return 0;
+
+	callback = rpm_get_suspend_cb(dev);
+
+	if (!callback) {
+		ret = -ENOSYS;
+		goto err;
+	}
+
+	ret = callback(dev);
+	if (ret)
+		goto err;
+
+	pm_runtime_set_suspended(dev);
+	return 0;
+err:
+	pm_runtime_enable(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_suspend);
+
+/**
+ * pm_runtime_force_resume - Force a device into resume state.
+ * @dev: Device to resume.
+ *
+ * Prior invoking this function we expect the user to have brought the device
+ * into low power state by a call to pm_runtime_force_suspend(). Here we reverse
+ * those actions and brings the device into full power. We update the runtime PM
+ * status and re-enables runtime PM.
+ *
+ * Typically this function may be invoked from a system resume callback to make
+ * sure the device is put into full power state.
+ */
+int pm_runtime_force_resume(struct device *dev)
+{
+	int (*callback)(struct device *);
+	int ret = 0;
+
+	callback = rpm_get_resume_cb(dev);
+
+	if (!callback) {
+		ret = -ENOSYS;
+		goto out;
+	}
+
+	ret = callback(dev);
+	if (ret)
+		goto out;
+
+	pm_runtime_set_active(dev);
+	pm_runtime_mark_last_busy(dev);
+out:
+	pm_runtime_enable(dev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(pm_runtime_force_resume);

drivers/base/power/sysfs.c

···
 static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
 		autosuspend_delay_ms_store);
 
-static ssize_t pm_qos_latency_show(struct device *dev,
-				   struct device_attribute *attr, char *buf)
+static ssize_t pm_qos_resume_latency_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
 {
-	return sprintf(buf, "%d\n", dev_pm_qos_requested_latency(dev));
+	return sprintf(buf, "%d\n", dev_pm_qos_requested_resume_latency(dev));
 }
 
-static ssize_t pm_qos_latency_store(struct device *dev,
-				    struct device_attribute *attr,
-				    const char *buf, size_t n)
+static ssize_t pm_qos_resume_latency_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t n)
 {
 	s32 value;
 	int ret;
···
 	if (value < 0)
 		return -EINVAL;
 
-	ret = dev_pm_qos_update_request(dev->power.qos->latency_req, value);
+	ret = dev_pm_qos_update_request(dev->power.qos->resume_latency_req,
+					value);
 	return ret < 0 ? ret : n;
 }
 
 static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
-		   pm_qos_latency_show, pm_qos_latency_store);
+		   pm_qos_resume_latency_show, pm_qos_resume_latency_store);
+
+static ssize_t pm_qos_latency_tolerance_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	s32 value = dev_pm_qos_get_user_latency_tolerance(dev);
+
+	if (value < 0)
+		return sprintf(buf, "auto\n");
+	else if (value == PM_QOS_LATENCY_ANY)
+		return sprintf(buf, "any\n");
+
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t pm_qos_latency_tolerance_store(struct device *dev,
+					      struct device_attribute *attr,
+					      const char *buf, size_t n)
+{
+	s32 value;
+	int ret;
+
+	if (kstrtos32(buf, 0, &value)) {
+		if (!strcmp(buf, "auto") || !strcmp(buf, "auto\n"))
+			value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
+		else if (!strcmp(buf, "any") || !strcmp(buf, "any\n"))
+			value = PM_QOS_LATENCY_ANY;
+	}
+	ret = dev_pm_qos_update_user_latency_tolerance(dev, value);
+	return ret < 0 ? ret : n;
+}
+
+static DEVICE_ATTR(pm_qos_latency_tolerance_us, 0644,
+		   pm_qos_latency_tolerance_show, pm_qos_latency_tolerance_store);
 
 static ssize_t pm_qos_no_power_off_show(struct device *dev,
 					struct device_attribute *attr,
···
 	.attrs	= runtime_attrs,
 };
 
-static struct attribute *pm_qos_latency_attrs[] = {
+static struct attribute *pm_qos_resume_latency_attrs[] = {
 #ifdef CONFIG_PM_RUNTIME
 	&dev_attr_pm_qos_resume_latency_us.attr,
 #endif /* CONFIG_PM_RUNTIME */
 	NULL,
 };
-static struct attribute_group pm_qos_latency_attr_group = {
+static struct attribute_group pm_qos_resume_latency_attr_group = {
 	.name	= power_group_name,
-	.attrs	= pm_qos_latency_attrs,
+	.attrs	= pm_qos_resume_latency_attrs,
+};
+
+static struct attribute *pm_qos_latency_tolerance_attrs[] = {
+#ifdef CONFIG_PM_RUNTIME
+	&dev_attr_pm_qos_latency_tolerance_us.attr,
+#endif /* CONFIG_PM_RUNTIME */
+	NULL,
+};
+static struct attribute_group pm_qos_latency_tolerance_attr_group = {
+	.name	= power_group_name,
+	.attrs	= pm_qos_latency_tolerance_attrs,
 };
 
 static struct attribute *pm_qos_flags_attrs[] = {
···
 		if (rc)
 			goto err_out;
 	}
-
 	if (device_can_wakeup(dev)) {
 		rc = sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
-		if (rc) {
-			if (pm_runtime_callbacks_present(dev))
-				sysfs_unmerge_group(&dev->kobj,
-						    &pm_runtime_attr_group);
-			goto err_out;
-		}
+		if (rc)
+			goto err_runtime;
+	}
+	if (dev->power.set_latency_tolerance) {
+		rc = sysfs_merge_group(&dev->kobj,
+				       &pm_qos_latency_tolerance_attr_group);
+		if (rc)
+			goto err_wakeup;
 	}
 	return 0;
 
+ err_wakeup:
+	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
+ err_runtime:
+	sysfs_unmerge_group(&dev->kobj, &pm_runtime_attr_group);
  err_out:
 	sysfs_remove_group(&dev->kobj, &pm_attr_group);
 	return rc;
···
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
 }
 
-int pm_qos_sysfs_add_latency(struct device *dev)
+int pm_qos_sysfs_add_resume_latency(struct device *dev)
 {
-	return sysfs_merge_group(&dev->kobj, &pm_qos_latency_attr_group);
+	return sysfs_merge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
 }
 
-void pm_qos_sysfs_remove_latency(struct device *dev)
+void pm_qos_sysfs_remove_resume_latency(struct device *dev)
 {
-	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_attr_group);
+	sysfs_unmerge_group(&dev->kobj, &pm_qos_resume_latency_attr_group);
 }
 
 int pm_qos_sysfs_add_flags(struct device *dev)
···
 
 void dpm_sysfs_remove(struct device *dev)
 {
+	sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group);
 	dev_pm_qos_constraints_destroy(dev);
 	rpm_sysfs_remove(dev);
 	sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);

drivers/input/touchscreen/st1232.c

···
 	} else if (!ts->low_latency_req.dev) {
 		/* First contact, request 100 us latency. */
 		dev_pm_qos_add_ancestor_request(&ts->client->dev,
-						&ts->low_latency_req, 100);
+						&ts->low_latency_req,
+						DEV_PM_QOS_RESUME_LATENCY, 100);
 	}
 
 	/* SYN_REPORT */

drivers/mtd/nand/sh_flctl.c

···
 		if (!flctl->qos_request) {
 			ret = dev_pm_qos_add_request(&flctl->pdev->dev,
 							&flctl->pm_qos,
-							DEV_PM_QOS_LATENCY,
+							DEV_PM_QOS_RESUME_LATENCY,
 							100);
 			if (ret < 0)
 				dev_err(&flctl->pdev->dev,

include/acpi/acpi_bus.h

···
 	struct list_head list_node;
 	int (*attach)(struct acpi_device *dev, const struct acpi_device_id *id);
 	void (*detach)(struct acpi_device *dev);
+	void (*bind)(struct device *phys_dev);
+	void (*unbind)(struct device *phys_dev);
 	struct acpi_hotplug_profile hotplug;
 };
 

include/linux/pm.h

···
 	unsigned long		accounting_timestamp;
 #endif
 	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
+	void (*set_latency_tolerance)(struct device *, s32);
 	struct dev_pm_qos	*qos;
 };
 

include/linux/pm_qos.h

···
 #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE	(2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_LAT_DEFAULT_VALUE	(2000 * USEC_PER_SEC)
 #define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE	0
-#define PM_QOS_DEV_LAT_DEFAULT_VALUE		0
+#define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE	0
+#define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE	0
+#define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT	(-1)
+#define PM_QOS_LATENCY_ANY			((s32)(~(__u32)0 >> 1))
 
 #define PM_QOS_FLAG_NO_POWER_OFF	(1 << 0)
 #define PM_QOS_FLAG_REMOTE_WAKEUP	(1 << 1)
···
 };
 
 enum dev_pm_qos_req_type {
-	DEV_PM_QOS_LATENCY = 1,
+	DEV_PM_QOS_RESUME_LATENCY = 1,
+	DEV_PM_QOS_LATENCY_TOLERANCE,
 	DEV_PM_QOS_FLAGS,
 };
 
···
 	struct plist_head list;
 	s32 target_value;	/* Do not change to 64 bit */
 	s32 default_value;
+	s32 no_constraint_value;
 	enum pm_qos_type type;
 	struct blocking_notifier_head *notifiers;
 };
···
 };
 
 struct dev_pm_qos {
-	struct pm_qos_constraints latency;
+	struct pm_qos_constraints resume_latency;
+	struct pm_qos_constraints latency_tolerance;
 	struct pm_qos_flags flags;
-	struct dev_pm_qos_request *latency_req;
+	struct dev_pm_qos_request *resume_latency_req;
+	struct dev_pm_qos_request *latency_tolerance_req;
 	struct dev_pm_qos_request *flags_req;
 };
 
···
 void dev_pm_qos_constraints_init(struct device *dev);
 void dev_pm_qos_constraints_destroy(struct device *dev);
 int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value);
+				    struct dev_pm_qos_request *req,
+				    enum dev_pm_qos_req_type type, s32 value);
 #else
 static inline enum pm_qos_flags_status __dev_pm_qos_flags(struct device *dev,
 							  s32 mask)
···
 	dev->power.power_state = PMSG_INVALID;
 }
 static inline int dev_pm_qos_add_ancestor_request(struct device *dev,
-				    struct dev_pm_qos_request *req, s32 value)
+						  struct dev_pm_qos_request *req,
+						  enum dev_pm_qos_req_type type,
+						  s32 value)
 			{ return 0; }
 #endif
 
···
 int dev_pm_qos_expose_flags(struct device *dev, s32 value);
 void dev_pm_qos_hide_flags(struct device *dev);
 int dev_pm_qos_update_flags(struct device *dev, s32 mask, bool set);
+s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev);
+int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val);
 
-static inline s32 dev_pm_qos_requested_latency(struct device *dev)
+static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev)
 {
-	return dev->power.qos->latency_req->data.pnode.prio;
+	return dev->power.qos->resume_latency_req->data.pnode.prio;
 }
 
 static inline s32 dev_pm_qos_requested_flags(struct device *dev)
···
 static inline void dev_pm_qos_hide_flags(struct device *dev) {}
 static inline int dev_pm_qos_update_flags(struct device *dev, s32 m, bool set)
 			{ return 0; }
+static inline s32 dev_pm_qos_get_user_latency_tolerance(struct device *dev)
+			{ return PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; }
+static inline int dev_pm_qos_update_user_latency_tolerance(struct device *dev, s32 val)
+			{ return 0; }
 
-static inline s32 dev_pm_qos_requested_latency(struct device *dev) { return 0; }
+static inline s32 dev_pm_qos_requested_resume_latency(struct device *dev) { return 0; }
 static inline s32 dev_pm_qos_requested_flags(struct device *dev) { return 0; }
 #endif
 

include/linux/pm_runtime.h

···
 #ifdef CONFIG_PM
 extern int pm_generic_runtime_suspend(struct device *dev);
 extern int pm_generic_runtime_resume(struct device *dev);
+extern int pm_runtime_force_suspend(struct device *dev);
+extern int pm_runtime_force_resume(struct device *dev);
 #else
 static inline int pm_generic_runtime_suspend(struct device *dev) { return 0; }
 static inline int pm_generic_runtime_resume(struct device *dev) { return 0; }
+static inline int pm_runtime_force_suspend(struct device *dev) { return 0; }
+static inline int pm_runtime_force_resume(struct device *dev) { return 0; }
 #endif
 
 #ifdef CONFIG_PM_RUNTIME

include/trace/events/power.h

···
 	TP_printk("device=%s type=%s new_value=%d",
 		  __get_str(name),
 		  __print_symbolic(__entry->type,
-			{ DEV_PM_QOS_LATENCY,	"DEV_PM_QOS_LATENCY" },
-			{ DEV_PM_QOS_FLAGS,	"DEV_PM_QOS_FLAGS" }),
+			{ DEV_PM_QOS_RESUME_LATENCY, "DEV_PM_QOS_RESUME_LATENCY" },
+			{ DEV_PM_QOS_FLAGS, "DEV_PM_QOS_FLAGS" }),
 		  __entry->new_value)
 );
 

kernel/power/qos.c

···
 	.list = PLIST_HEAD_INIT(cpu_dma_constraints.list),
 	.target_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.default_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE,
 	.type = PM_QOS_MIN,
 	.notifiers = &cpu_dma_lat_notifier,
 };
···
 	.list = PLIST_HEAD_INIT(network_lat_constraints.list),
 	.target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
 	.default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
 	.type = PM_QOS_MIN,
 	.notifiers = &network_lat_notifier,
 };
···
 	.list = PLIST_HEAD_INIT(network_tput_constraints.list),
 	.target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
 	.default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
+	.no_constraint_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
 	.type = PM_QOS_MAX,
 	.notifiers = &network_throughput_notifier,
 };
···
 static inline int pm_qos_get_value(struct pm_qos_constraints *c)
 {
 	if (plist_head_empty(&c->list))
-		return c->default_value;
+		return c->no_constraint_value;
 
 	switch (c->type) {
 	case PM_QOS_MIN:
···
 {
 	unsigned long flags;
 	int prev_value, curr_value, new_value;
+	int ret;
 
 	spin_lock_irqsave(&pm_qos_lock, flags);
 	prev_value = pm_qos_get_value(c);
···
 
 	trace_pm_qos_update_target(action, prev_value, curr_value);
 	if (prev_value != curr_value) {
-		blocking_notifier_call_chain(c->notifiers,
-					     (unsigned long)curr_value,
-					     NULL);
-		return 1;
+		ret = 1;
+		if (c->notifiers)
+			blocking_notifier_call_chain(c->notifiers,
+						     (unsigned long)curr_value,
+						     NULL);
 	} else {
-		return 0;
+		ret = 0;
 	}
+	return ret;
 }
 
 /**