7 files changed, 252 insertions, 132 deletions

diff --git a/Documentation/driver-api/pm/devices.rst b/Documentation/driver-api/pm/devices.rst
index 53c1b0b06da5..b0fe63c91f8d 100644
--- a/Documentation/driver-api/pm/devices.rst
+++ b/Documentation/driver-api/pm/devices.rst
@@ -788,6 +788,29 @@ must reflect the "active" status for runtime PM in that case.
 
 During system-wide resume from a sleep state it's easiest to put devices into
 the full-power state, as explained in :file:`Documentation/power/runtime_pm.txt`.
-Refer to that document for more information regarding this particular issue as
+[Refer to that document for more information regarding this particular issue as
 well as for information on the device runtime power management framework in
-general.
+general.]
+
+However, it often is desirable to leave devices in suspend after system
+transitions to the working state, especially if those devices had been in
+runtime suspend before the preceding system-wide suspend (or analogous)
+transition.  Device drivers can use the ``DPM_FLAG_LEAVE_SUSPENDED`` flag to
+indicate to the PM core (and middle-layer code) that they prefer the specific
+devices handled by them to be left suspended and they have no problems with
+skipping their system-wide resume callbacks for this reason.  Whether or not the
+devices will actually be left in suspend may depend on their state before the
+given system suspend-resume cycle and on the type of the system transition under
+way.  In particular, devices are not left suspended if that transition is a
+restore from hibernation, as device states are not guaranteed to be reflected
+by the information stored in the hibernation image in that case.
+
+The middle-layer code involved in the handling of the device is expected to
+indicate to the PM core if the device may be left in suspend by setting its
+:c:member:`power.may_skip_resume` status bit which is checked by the PM core
+during the "noirq" phase of the preceding system-wide suspend (or analogous)
+transition.  The middle layer is then responsible for handling the device as
+appropriate in its "noirq" resume callback, which is executed regardless of
+whether or not the device is left suspended, but the other resume callbacks
+(except for ``->complete``) will be skipped automatically by the PM core if the
+device really can be left in suspend.
diff --git a/Documentation/power/pci.txt b/Documentation/power/pci.txt
index 704cd36079b8..8eaf9ee24d43 100644
--- a/Documentation/power/pci.txt
+++ b/Documentation/power/pci.txt
@@ -994,6 +994,17 @@ into D0 going forward), but if it is in runtime suspend in pci_pm_thaw_noirq(),
 the function will set the power.direct_complete flag for it (to make the PM core
 skip the subsequent "thaw" callbacks for it) and return.
 
+Setting the DPM_FLAG_LEAVE_SUSPENDED flag means that the driver prefers the
+device to be left in suspend after system-wide transitions to the working state.
+This flag is checked by the PM core, but the PCI bus type informs the PM core
+which devices may be left in suspend from its perspective (that happens during
+the "noirq" phase of system-wide suspend and analogous transitions) and next it
+uses the dev_pm_may_skip_resume() helper to decide whether or not to return from
+pci_pm_resume_noirq() early, as the PM core will skip the remaining resume
+callbacks for the device during the transition under way and will set its
+runtime PM status to "suspended" if dev_pm_may_skip_resume() returns "true" for
+it.
+
 3.2. Device Runtime Power Management
 ------------------------------------
 In addition to providing device power management callbacks PCI device drivers
diff --git a/drivers/acpi/device_pm.c b/drivers/acpi/device_pm.c
index a4c8ad98560d..c4d0a1c912f0 100644
--- a/drivers/acpi/device_pm.c
+++ b/drivers/acpi/device_pm.c
@@ -990,7 +990,7 @@ void acpi_subsys_complete(struct device *dev)
          * the sleep state it is going out of and it has never been resumed till
          * now, resume it in case the firmware powered it up.
          */
-        if (dev->power.direct_complete && pm_resume_via_firmware())
+        if (pm_runtime_suspended(dev) && pm_resume_via_firmware())
                 pm_request_resume(dev);
 }
 EXPORT_SYMBOL_GPL(acpi_subsys_complete);
@@ -1039,10 +1039,28 @@ EXPORT_SYMBOL_GPL(acpi_subsys_suspend_late);
  */
 int acpi_subsys_suspend_noirq(struct device *dev)
 {
-        if (dev_pm_smart_suspend_and_suspended(dev))
+        int ret;
+
+        if (dev_pm_smart_suspend_and_suspended(dev)) {
+                dev->power.may_skip_resume = true;
                 return 0;
+        }
+
+        ret = pm_generic_suspend_noirq(dev);
+        if (ret)
+                return ret;
+
+        /*
+         * If the target system sleep state is suspend-to-idle, it is sufficient
+         * to check whether or not the device's wakeup settings are good for
+         * runtime PM.  Otherwise, the pm_resume_via_firmware() check will cause
+         * acpi_subsys_complete() to take care of fixing up the device's state
+         * anyway, if need be.
+         */
+        dev->power.may_skip_resume = device_may_wakeup(dev) ||
+                                        !device_can_wakeup(dev);
 
-        return pm_generic_suspend_noirq(dev);
+        return 0;
 }
 EXPORT_SYMBOL_GPL(acpi_subsys_suspend_noirq);
 
@@ -1052,6 +1070,9 @@ EXPORT_SYMBOL_GPL(acpi_subsys_suspend_noirq);
  */
 int acpi_subsys_resume_noirq(struct device *dev)
 {
+        if (dev_pm_may_skip_resume(dev))
+                return 0;
+
         /*
          * Devices with DPM_FLAG_SMART_SUSPEND may be left in runtime suspend
          * during system suspend, so update their runtime PM status to "active"
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 08744b572af6..6e8cc5de93fd 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -18,7 +18,6 @@
  */
 
 #include <linux/device.h>
-#include <linux/kallsyms.h>
 #include <linux/export.h>
 #include <linux/mutex.h>
 #include <linux/pm.h>
@@ -541,6 +540,18 @@ void dev_pm_skip_next_resume_phases(struct device *dev)
 }
 
 /**
+ * dev_pm_may_skip_resume - System-wide device resume optimization check.
+ * @dev: Target device.
+ *
+ * Checks whether or not the device may be left in suspend after a system-wide
+ * transition to the working state.
+ */
+bool dev_pm_may_skip_resume(struct device *dev)
+{
+        return !dev->power.must_resume && pm_transition.event != PM_EVENT_RESTORE;
+}
+
+/**
  * device_resume_noirq - Execute a "noirq resume" callback for given device.
  * @dev: Device to handle.
  * @state: PM transition of the system being carried out.
@@ -588,6 +599,18 @@ static int device_resume_noirq(struct device *dev, pm_message_t state, bool asyn
         error = dpm_run_callback(callback, dev, state, info);
         dev->power.is_noirq_suspended = false;
 
+        if (dev_pm_may_skip_resume(dev)) {
+                /*
+                 * The device is going to be left in suspend, but it might not
+                 * have been in runtime suspend before the system suspended, so
+                 * its runtime PM status needs to be updated to avoid confusing
+                 * the runtime PM framework when runtime PM is enabled for the
+                 * device again.
+                 */
+                pm_runtime_set_suspended(dev);
+                dev_pm_skip_next_resume_phases(dev);
+        }
+
  Out:
         complete_all(&dev->power.completion);
         TRACE_RESUME(error);
@@ -1089,6 +1112,22 @@ static pm_message_t resume_event(pm_message_t sleep_state)
         return PMSG_ON;
 }
 
+static void dpm_superior_set_must_resume(struct device *dev)
+{
+        struct device_link *link;
+        int idx;
+
+        if (dev->parent)
+                dev->parent->power.must_resume = true;
+
+        idx = device_links_read_lock();
+
+        list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+                link->supplier->power.must_resume = true;
+
+        device_links_read_unlock(idx);
+}
+
 /**
  * __device_suspend_noirq - Execute a "noirq suspend" callback for given device.
  * @dev: Device to handle.
@@ -1140,10 +1179,28 @@ static int __device_suspend_noirq(struct device *dev, pm_message_t state, bool a
         }
 
         error = dpm_run_callback(callback, dev, state, info);
-        if (!error)
-                dev->power.is_noirq_suspended = true;
-        else
+        if (error) {
                 async_error = error;
+                goto Complete;
+        }
+
+        dev->power.is_noirq_suspended = true;
+
+        if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED)) {
+                /*
+                 * The only safe strategy here is to require that if the device
+                 * may not be left in suspend, resume callbacks must be invoked
+                 * for it.
+                 */
+                dev->power.must_resume = dev->power.must_resume ||
+                                        !dev->power.may_skip_resume ||
+                                        atomic_read(&dev->power.usage_count) > 1;
+        } else {
+                dev->power.must_resume = true;
+        }
+
+        if (dev->power.must_resume)
+                dpm_superior_set_must_resume(dev);
 
 Complete:
         complete_all(&dev->power.completion);
@@ -1435,6 +1492,22 @@ static int legacy_suspend(struct device *dev, pm_message_t state,
         return error;
 }
 
+static void dpm_propagate_to_parent(struct device *dev)
+{
+        struct device *parent = dev->parent;
+
+        if (!parent)
+                return;
+
+        spin_lock_irq(&parent->power.lock);
+
+        parent->power.direct_complete = false;
+        if (dev->power.wakeup_path && !parent->power.ignore_children)
+                parent->power.wakeup_path = true;
+
+        spin_unlock_irq(&parent->power.lock);
+}
+
 static void dpm_clear_suppliers_direct_complete(struct device *dev)
 {
         struct device_link *link;
@@ -1500,6 +1573,9 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
                 dev->power.direct_complete = false;
         }
 
+        dev->power.may_skip_resume = false;
+        dev->power.must_resume = false;
+
         dpm_watchdog_set(&wd, dev);
         device_lock(dev);
 
@@ -1543,19 +1619,8 @@ static int __device_suspend(struct device *dev, pm_message_t state, bool async)
 
  End:
         if (!error) {
-                struct device *parent = dev->parent;
-
                 dev->power.is_suspended = true;
-                if (parent) {
-                        spin_lock_irq(&parent->power.lock);
-
-                        dev->parent->power.direct_complete = false;
-                        if (dev->power.wakeup_path
-                            && !dev->parent->power.ignore_children)
-                                dev->parent->power.wakeup_path = true;
-
-                        spin_unlock_irq(&parent->power.lock);
-                }
+                dpm_propagate_to_parent(dev);
                 dpm_clear_suppliers_direct_complete(dev);
         }
 
@@ -1665,8 +1730,9 @@ static int device_prepare(struct device *dev, pm_message_t state)
         if (dev->power.syscore)
                 return 0;
 
-        WARN_ON(dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) &&
-                !pm_runtime_enabled(dev));
+        WARN_ON(!pm_runtime_enabled(dev) &&
+                dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND |
+                                              DPM_FLAG_LEAVE_SUSPENDED));
 
         /*
          * If a device's parent goes into runtime suspend at the wrong time,
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index e153e28b1857..0f651efc58a1 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -108,16 +108,10 @@ static ssize_t control_show(struct device *dev, struct device_attribute *attr,
 static ssize_t control_store(struct device * dev, struct device_attribute *attr,
                              const char * buf, size_t n)
 {
-        char *cp;
-        int len = n;
-
-        cp = memchr(buf, '\n', n);
-        if (cp)
-                len = cp - buf;
         device_lock(dev);
-        if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
+        if (sysfs_streq(buf, ctrl_auto))
                 pm_runtime_allow(dev);
-        else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
+        else if (sysfs_streq(buf, ctrl_on))
                 pm_runtime_forbid(dev);
         else
                 n = -EINVAL;
@@ -125,9 +119,9 @@ static ssize_t control_store(struct device * dev, struct device_attribute *attr,
         return n;
 }
 
-static DEVICE_ATTR(control, 0644, control_show, control_store);
+static DEVICE_ATTR_RW(control);
 
-static ssize_t rtpm_active_time_show(struct device *dev,
+static ssize_t runtime_active_time_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
 {
         int ret;
@@ -138,9 +132,9 @@ static ssize_t rtpm_active_time_show(struct device *dev,
         return ret;
 }
 
-static DEVICE_ATTR(runtime_active_time, 0444, rtpm_active_time_show, NULL);
+static DEVICE_ATTR_RO(runtime_active_time);
 
-static ssize_t rtpm_suspended_time_show(struct device *dev,
+static ssize_t runtime_suspended_time_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
 {
         int ret;
@@ -152,9 +146,9 @@ static ssize_t rtpm_suspended_time_show(struct device *dev,
         return ret;
 }
 
-static DEVICE_ATTR(runtime_suspended_time, 0444, rtpm_suspended_time_show, NULL);
+static DEVICE_ATTR_RO(runtime_suspended_time);
 
-static ssize_t rtpm_status_show(struct device *dev,
+static ssize_t runtime_status_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
 {
         const char *p;
@@ -184,7 +178,7 @@ static ssize_t rtpm_status_show(struct device *dev,
         return sprintf(buf, p);
 }
 
-static DEVICE_ATTR(runtime_status, 0444, rtpm_status_show, NULL);
+static DEVICE_ATTR_RO(runtime_status);
 
 static ssize_t autosuspend_delay_ms_show(struct device *dev,
                 struct device_attribute *attr, char *buf)
@@ -211,26 +205,25 @@ static ssize_t autosuspend_delay_ms_store(struct device *dev,
         return n;
 }
 
-static DEVICE_ATTR(autosuspend_delay_ms, 0644, autosuspend_delay_ms_show,
-                autosuspend_delay_ms_store);
+static DEVICE_ATTR_RW(autosuspend_delay_ms);
 
-static ssize_t pm_qos_resume_latency_show(struct device *dev,
-                                          struct device_attribute *attr,
-                                          char *buf)
+static ssize_t pm_qos_resume_latency_us_show(struct device *dev,
+                                             struct device_attribute *attr,
+                                             char *buf)
 {
         s32 value = dev_pm_qos_requested_resume_latency(dev);
 
         if (value == 0)
                 return sprintf(buf, "n/a\n");
-        else if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
+        if (value == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT)
                 value = 0;
 
         return sprintf(buf, "%d\n", value);
 }
 
-static ssize_t pm_qos_resume_latency_store(struct device *dev,
-                                           struct device_attribute *attr,
-                                           const char *buf, size_t n)
+static ssize_t pm_qos_resume_latency_us_store(struct device *dev,
+                                              struct device_attribute *attr,
+                                              const char *buf, size_t n)
 {
         s32 value;
         int ret;
@@ -245,7 +238,7 @@ static ssize_t pm_qos_resume_latency_store(struct device *dev,
 
                 if (value == 0)
                         value = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;
-        } else if (!strcmp(buf, "n/a") || !strcmp(buf, "n/a\n")) {
+        } else if (sysfs_streq(buf, "n/a")) {
                 value = 0;
         } else {
                 return -EINVAL;
@@ -256,26 +249,25 @@ static ssize_t pm_qos_resume_latency_store(struct device *dev,
         return ret < 0 ? ret : n;
 }
 
-static DEVICE_ATTR(pm_qos_resume_latency_us, 0644,
-                   pm_qos_resume_latency_show, pm_qos_resume_latency_store);
+static DEVICE_ATTR_RW(pm_qos_resume_latency_us);
 
-static ssize_t pm_qos_latency_tolerance_show(struct device *dev,
-                                             struct device_attribute *attr,
-                                             char *buf)
+static ssize_t pm_qos_latency_tolerance_us_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)
+        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)
+static ssize_t pm_qos_latency_tolerance_us_store(struct device *dev,
+                                                 struct device_attribute *attr,
+                                                 const char *buf, size_t n)
 {
         s32 value;
         int ret;
@@ -285,9 +277,9 @@ static ssize_t pm_qos_latency_tolerance_store(struct device *dev,
                 if (value < 0)
                         return -EINVAL;
         } else {
-                if (!strcmp(buf, "auto") || !strcmp(buf, "auto\n"))
+                if (sysfs_streq(buf, "auto"))
                         value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT;
-                else if (!strcmp(buf, "any") || !strcmp(buf, "any\n"))
+                else if (sysfs_streq(buf, "any"))
                         value = PM_QOS_LATENCY_ANY;
                 else
                         return -EINVAL;
@@ -296,8 +288,7 @@ static ssize_t pm_qos_latency_tolerance_store(struct device *dev,
         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 DEVICE_ATTR_RW(pm_qos_latency_tolerance_us);
 
 static ssize_t pm_qos_no_power_off_show(struct device *dev,
                                         struct device_attribute *attr,
@@ -323,49 +314,39 @@ static ssize_t pm_qos_no_power_off_store(struct device *dev,
         return ret < 0 ? ret : n;
 }
 
-static DEVICE_ATTR(pm_qos_no_power_off, 0644,
-                   pm_qos_no_power_off_show, pm_qos_no_power_off_store);
+static DEVICE_ATTR_RW(pm_qos_no_power_off);
 
 #ifdef CONFIG_PM_SLEEP
 static const char _enabled[] = "enabled";
 static const char _disabled[] = "disabled";
 
-static ssize_t
-wake_show(struct device * dev, struct device_attribute *attr, char * buf)
+static ssize_t wakeup_show(struct device *dev, struct device_attribute *attr,
+                           char *buf)
 {
         return sprintf(buf, "%s\n", device_can_wakeup(dev)
                 ? (device_may_wakeup(dev) ? _enabled : _disabled)
                 : "");
 }
 
-static ssize_t
-wake_store(struct device * dev, struct device_attribute *attr,
-        const char * buf, size_t n)
+static ssize_t wakeup_store(struct device *dev, struct device_attribute *attr,
+                            const char *buf, size_t n)
 {
-        char *cp;
-        int len = n;
-
         if (!device_can_wakeup(dev))
                 return -EINVAL;
 
-        cp = memchr(buf, '\n', n);
-        if (cp)
-                len = cp - buf;
-        if (len == sizeof _enabled - 1
-                        && strncmp(buf, _enabled, sizeof _enabled - 1) == 0)
+        if (sysfs_streq(buf, _enabled))
                 device_set_wakeup_enable(dev, 1);
-        else if (len == sizeof _disabled - 1
-                        && strncmp(buf, _disabled, sizeof _disabled - 1) == 0)
+        else if (sysfs_streq(buf, _disabled))
                 device_set_wakeup_enable(dev, 0);
         else
                 return -EINVAL;
         return n;
 }
 
-static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
+static DEVICE_ATTR_RW(wakeup);
 
 static ssize_t wakeup_count_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+                                 struct device_attribute *attr, char *buf)
 {
         unsigned long count = 0;
         bool enabled = false;
@@ -379,10 +360,11 @@ static ssize_t wakeup_count_show(struct device *dev,
         return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_count, 0444, wakeup_count_show, NULL);
+static DEVICE_ATTR_RO(wakeup_count);
 
 static ssize_t wakeup_active_count_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+                                        struct device_attribute *attr,
+                                        char *buf)
 {
         unsigned long count = 0;
         bool enabled = false;
@@ -396,11 +378,11 @@ static ssize_t wakeup_active_count_show(struct device *dev,
         return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_active_count, 0444, wakeup_active_count_show, NULL);
+static DEVICE_ATTR_RO(wakeup_active_count);
 
 static ssize_t wakeup_abort_count_show(struct device *dev,
-                                        struct device_attribute *attr,
-                                        char *buf)
+                                       struct device_attribute *attr,
+                                       char *buf)
 {
         unsigned long count = 0;
         bool enabled = false;
@@ -414,7 +396,7 @@ static ssize_t wakeup_abort_count_show(struct device *dev,
         return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_abort_count, 0444, wakeup_abort_count_show, NULL);
+static DEVICE_ATTR_RO(wakeup_abort_count);
 
 static ssize_t wakeup_expire_count_show(struct device *dev,
                                         struct device_attribute *attr,
@@ -432,10 +414,10 @@ static ssize_t wakeup_expire_count_show(struct device *dev,
         return enabled ? sprintf(buf, "%lu\n", count) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_expire_count, 0444, wakeup_expire_count_show, NULL);
+static DEVICE_ATTR_RO(wakeup_expire_count);
 
 static ssize_t wakeup_active_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+                                  struct device_attribute *attr, char *buf)
 {
         unsigned int active = 0;
         bool enabled = false;
@@ -449,10 +431,11 @@ static ssize_t wakeup_active_show(struct device *dev,
         return enabled ? sprintf(buf, "%u\n", active) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_active, 0444, wakeup_active_show, NULL);
+static DEVICE_ATTR_RO(wakeup_active);
 
-static ssize_t wakeup_total_time_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+static ssize_t wakeup_total_time_ms_show(struct device *dev,
+                                         struct device_attribute *attr,
+                                         char *buf)
 {
         s64 msec = 0;
         bool enabled = false;
@@ -466,10 +449,10 @@ static ssize_t wakeup_total_time_show(struct device *dev,
         return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_total_time_ms, 0444, wakeup_total_time_show, NULL);
+static DEVICE_ATTR_RO(wakeup_total_time_ms);
 
-static ssize_t wakeup_max_time_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+static ssize_t wakeup_max_time_ms_show(struct device *dev,
+                                       struct device_attribute *attr, char *buf)
 {
         s64 msec = 0;
         bool enabled = false;
@@ -483,10 +466,11 @@ static ssize_t wakeup_max_time_show(struct device *dev,
         return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_max_time_ms, 0444, wakeup_max_time_show, NULL);
+static DEVICE_ATTR_RO(wakeup_max_time_ms);
 
-static ssize_t wakeup_last_time_show(struct device *dev,
-                                struct device_attribute *attr, char *buf)
+static ssize_t wakeup_last_time_ms_show(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
 {
         s64 msec = 0;
         bool enabled = false;
@@ -500,12 +484,12 @@ static ssize_t wakeup_last_time_show(struct device *dev,
         return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_last_time_ms, 0444, wakeup_last_time_show, NULL);
+static DEVICE_ATTR_RO(wakeup_last_time_ms);
 
 #ifdef CONFIG_PM_AUTOSLEEP
-static ssize_t wakeup_prevent_sleep_time_show(struct device *dev,
-                                              struct device_attribute *attr,
-                                              char *buf)
+static ssize_t wakeup_prevent_sleep_time_ms_show(struct device *dev,
+                                                 struct device_attribute *attr,
+                                                 char *buf)
 {
         s64 msec = 0;
         bool enabled = false;
@@ -519,40 +503,39 @@ static ssize_t wakeup_prevent_sleep_time_show(struct device *dev,
         return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n");
 }
 
-static DEVICE_ATTR(wakeup_prevent_sleep_time_ms, 0444,
-                   wakeup_prevent_sleep_time_show, NULL);
+static DEVICE_ATTR_RO(wakeup_prevent_sleep_time_ms);
 #endif /* CONFIG_PM_AUTOSLEEP */
 #endif /* CONFIG_PM_SLEEP */
 
 #ifdef CONFIG_PM_ADVANCED_DEBUG
-static ssize_t rtpm_usagecount_show(struct device *dev,
-                                    struct device_attribute *attr, char *buf)
+static ssize_t runtime_usage_show(struct device *dev,
+                                  struct device_attribute *attr, char *buf)
 {
         return sprintf(buf, "%d\n", atomic_read(&dev->power.usage_count));
 }
+static DEVICE_ATTR_RO(runtime_usage);
 
-static ssize_t rtpm_children_show(struct device *dev,
-                                  struct device_attribute *attr, char *buf)
+static ssize_t runtime_active_kids_show(struct device *dev,
+                                        struct device_attribute *attr,
+                                        char *buf)
 {
         return sprintf(buf, "%d\n", dev->power.ignore_children ?
                 0 : atomic_read(&dev->power.child_count));
 }
+static DEVICE_ATTR_RO(runtime_active_kids);
 
-static ssize_t rtpm_enabled_show(struct device *dev,
-                                 struct device_attribute *attr, char *buf)
+static ssize_t runtime_enabled_show(struct device *dev,
+                                    struct device_attribute *attr, char *buf)
 {
-        if ((dev->power.disable_depth) && (dev->power.runtime_auto == false))
+        if (dev->power.disable_depth && (dev->power.runtime_auto == false))
                 return sprintf(buf, "disabled & forbidden\n");
-        else if (dev->power.disable_depth)
+        if (dev->power.disable_depth)
                 return sprintf(buf, "disabled\n");
-        else if (dev->power.runtime_auto == false)
+        if (dev->power.runtime_auto == false)
                 return sprintf(buf, "forbidden\n");
         return sprintf(buf, "enabled\n");
 }
-
-static DEVICE_ATTR(runtime_usage, 0444, rtpm_usagecount_show, NULL);
-static DEVICE_ATTR(runtime_active_kids, 0444, rtpm_children_show, NULL);
-static DEVICE_ATTR(runtime_enabled, 0444, rtpm_enabled_show, NULL);
+static DEVICE_ATTR_RO(runtime_enabled);
 
 #ifdef CONFIG_PM_SLEEP
 static ssize_t async_show(struct device *dev, struct device_attribute *attr,
@@ -566,23 +549,16 @@ static ssize_t async_show(struct device *dev, struct device_attribute *attr,
 static ssize_t async_store(struct device *dev, struct device_attribute *attr,
                            const char *buf, size_t n)
 {
-        char *cp;
-        int len = n;
-
-        cp = memchr(buf, '\n', n);
-        if (cp)
-                len = cp - buf;
-        if (len == sizeof _enabled - 1 && strncmp(buf, _enabled, len) == 0)
+        if (sysfs_streq(buf, _enabled))
                 device_enable_async_suspend(dev);
-        else if (len == sizeof _disabled - 1 &&
-                 strncmp(buf, _disabled, len) == 0)
+        else if (sysfs_streq(buf, _disabled))
                 device_disable_async_suspend(dev);
         else
                 return -EINVAL;
         return n;
 }
 
-static DEVICE_ATTR(async, 0644, async_show, async_store);
+static DEVICE_ATTR_RW(async);
 
 #endif /* CONFIG_PM_SLEEP */
 #endif /* CONFIG_PM_ADVANCED_DEBUG */
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 945099d49f8f..9e53e51b91f3 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -699,7 +699,7 @@ static void pci_pm_complete(struct device *dev)
         pm_generic_complete(dev);
 
         /* Resume device if platform firmware has put it in reset-power-on */
-        if (dev->power.direct_complete && pm_resume_via_firmware()) {
+        if (pm_runtime_suspended(dev) && pm_resume_via_firmware()) {
                 pci_power_t pre_sleep_state = pci_dev->current_state;
 
                 pci_update_current_state(pci_dev, pci_dev->current_state);
@@ -783,8 +783,10 @@ static int pci_pm_suspend_noirq(struct device *dev)
         struct pci_dev *pci_dev = to_pci_dev(dev);
         const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
 
-        if (dev_pm_smart_suspend_and_suspended(dev))
+        if (dev_pm_smart_suspend_and_suspended(dev)) {
+                dev->power.may_skip_resume = true;
                 return 0;
+        }
 
         if (pci_has_legacy_pm_support(pci_dev))
                 return pci_legacy_suspend_late(dev, PMSG_SUSPEND);
@@ -838,6 +840,16 @@ static int pci_pm_suspend_noirq(struct device *dev)
 Fixup:
         pci_fixup_device(pci_fixup_suspend_late, pci_dev);
 
+        /*
+         * If the target system sleep state is suspend-to-idle, it is sufficient
+         * to check whether or not the device's wakeup settings are good for
+         * runtime PM.  Otherwise, the pm_resume_via_firmware() check will cause
+         * pci_pm_complete() to take care of fixing up the device's state
+         * anyway, if need be.
+         */
+        dev->power.may_skip_resume = device_may_wakeup(dev) ||
+                                        !device_can_wakeup(dev);
+
         return 0;
 }
 
@@ -847,6 +859,9 @@ static int pci_pm_resume_noirq(struct device *dev)
         struct device_driver *drv = dev->driver;
         int error = 0;
 
+        if (dev_pm_may_skip_resume(dev))
+                return 0;
+
         /*
          * Devices with DPM_FLAG_SMART_SUSPEND may be left in runtime suspend
          * during system suspend, so update their runtime PM status to "active"
diff --git a/include/linux/pm.h b/include/linux/pm.h
index 492ed473ba7e..e723b78d8357 100644
--- a/include/linux/pm.h
+++ b/include/linux/pm.h
@@ -556,9 +556,10 @@ struct pm_subsys_data {
  * These flags can be set by device drivers at the probe time.  They need not be
  * cleared by the drivers as the driver core will take care of that.
  *
- * NEVER_SKIP: Do not skip system suspend/resume callbacks for the device.
+ * NEVER_SKIP: Do not skip all system suspend/resume callbacks for the device.
  * SMART_PREPARE: Check the return value of the driver's ->prepare callback.
  * SMART_SUSPEND: No need to resume the device from runtime suspend.
+ * LEAVE_SUSPENDED: Avoid resuming the device during system resume if possible.
  *
  * Setting SMART_PREPARE instructs bus types and PM domains which may want
  * system suspend/resume callbacks to be skipped for the device to return 0 from
@@ -572,10 +573,14 @@ struct pm_subsys_data {
  * necessary from the driver's perspective.  It also may cause them to skip
  * invocations of the ->suspend_late and ->suspend_noirq callbacks provided by
  * the driver if they decide to leave the device in runtime suspend.
+ *
+ * Setting LEAVE_SUSPENDED informs the PM core and middle-layer code that the
+ * driver prefers the device to be left in suspend after system resume.
  */
-#define DPM_FLAG_NEVER_SKIP     BIT(0)
-#define DPM_FLAG_SMART_PREPARE  BIT(1)
-#define DPM_FLAG_SMART_SUSPEND  BIT(2)
+#define DPM_FLAG_NEVER_SKIP             BIT(0)
+#define DPM_FLAG_SMART_PREPARE          BIT(1)
+#define DPM_FLAG_SMART_SUSPEND          BIT(2)
+#define DPM_FLAG_LEAVE_SUSPENDED        BIT(3)
 
 struct dev_pm_info {
         pm_message_t            power_state;
@@ -597,6 +602,8 @@ struct dev_pm_info {
         bool                    wakeup_path:1;
         bool                    syscore:1;
         bool                    no_pm_callbacks:1;      /* Owned by the PM core */
+        unsigned int            must_resume:1;  /* Owned by the PM core */
+        unsigned int            may_skip_resume:1;      /* Set by subsystems */
 #else
         unsigned int            should_wakeup:1;
 #endif
@@ -766,6 +773,7 @@ extern int pm_generic_poweroff(struct device *dev);
 extern void pm_generic_complete(struct device *dev);
 
 extern void dev_pm_skip_next_resume_phases(struct device *dev);
+extern bool dev_pm_may_skip_resume(struct device *dev);
 extern bool dev_pm_smart_suspend_and_suspended(struct device *dev);
 
 #else /* !CONFIG_PM_SLEEP */