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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Alan Stern <stern@rowland.harvard.edu>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux ACPI <linux-acpi@vger.kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Linux Documentation <linux-doc@vger.kernel.org>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Kevin Hilman <khilman@kernel.org>,
	Wolfram Sang <wsa@the-dreams.de>,
	linux-i2c@vger.kernel.org, Lee Jones <lee.jones@linaro.org>
Subject: [PATCH 10/12] PM / core: Add LEAVE_SUSPENDED driver flag
Date: Mon, 16 Oct 2017 03:30:22 +0200	[thread overview]
Message-ID: <1571653.x1WQWp6nIP@aspire.rjw.lan> (raw)
In-Reply-To: <3806130.B2KCK0tvef@aspire.rjw.lan>

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Define and document a new driver flag, DPM_FLAG_LEAVE_SUSPENDED, to
instruct the PM core that it is desirable to leave the device in
runtime suspend after system resume (for example, the device may be
slow to resume and it may be better to avoid resuming it right away
for this reason).

Setting that flag causes the PM core to skip the ->resume_noirq,
->resume_early and ->resume callbacks for the device (like in the
direct-complete optimization case) if (1) the wakeup settings of it
are compatible with runtime PM (that is, either the device is
configured to wake up the system from sleep or it cannot generate
wakeup signals at all), and it will not be used for resuming any of
its children or consumers.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 Documentation/driver-api/pm/devices.rst |   20 +++++++
 drivers/base/power/main.c               |   81 ++++++++++++++++++++++++++++++--
 include/linux/pm.h                      |   12 +++-
 3 files changed, 104 insertions(+), 9 deletions(-)

Index: linux-pm/include/linux/pm.h
===================================================================
--- linux-pm.orig/include/linux/pm.h
+++ linux-pm/include/linux/pm.h
@@ -559,6 +559,7 @@ struct pm_subsys_data {
  * NEVER_SKIP: Do not skip 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
@@ -573,10 +574,14 @@ struct pm_subsys_data {
  * the "late" and "noirq" phases of device suspend for the device if it remains
  * in runtime suspend at the beginning of the "late" phase (when runtime PM has
  * been disabled for it).
+ *
+ * Setting LEAVE_SUSPENDED informs the PM core and middle layer code that the
+ * driver prefers the device to be left in runtime 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;
@@ -598,6 +603,7 @@ 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 */
 #else
 	unsigned int		should_wakeup:1;
 #endif
Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -705,6 +705,12 @@ static int device_resume_early(struct de
 	if (!dev->power.is_late_suspended)
 		goto Out;
 
+	if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED) &&
+	    !dev->power.must_resume) {
+		pm_runtime_set_suspended(dev);
+		goto Out;
+	}
+
 	dpm_wait_for_superior(dev, async);
 
 	if (dev->pm_domain) {
@@ -1098,6 +1104,32 @@ static pm_message_t resume_event(pm_mess
 	return PMSG_ON;
 }
 
+static void dpm_suppliers_set_must_resume(struct device *dev)
+{
+	struct device_link *link;
+	int idx;
+
+	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);
+}
+
+static void dpm_leave_suspended(struct device *dev)
+{
+	pm_runtime_set_suspended(dev);
+	dev->power.is_suspended = false;
+	dev->power.is_late_suspended = false;
+	/*
+	 * This tells middle layer code to schedule runtime resume of the device
+	 * from its ->complete callback to update the device's power state in
+	 * case the platform firmware has been involved in resuming the system.
+	 */
+	dev->power.direct_complete = true;
+}
+
 /**
  * __device_suspend_noirq - Execute a "noirq suspend" callback for given device.
  * @dev: Device to handle.
@@ -1135,8 +1167,20 @@ static int __device_suspend_noirq(struct
 	 * the callback invocation for them.
 	 */
 	if (dev_pm_test_driver_flags(dev, DPM_FLAG_SMART_SUSPEND) &&
-	    pm_runtime_status_suspended(dev))
-		goto Skip;
+	    pm_runtime_status_suspended(dev)) {
+		/*
+		 * The device may be left suspended during system resume if
+		 * that is preferred by its driver and it will not be used for
+		 * resuming any of its children or consumers.
+		 */
+		if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED) &&
+		    !dev->power.must_resume) {
+			dpm_leave_suspended(dev);
+			goto Complete;
+		} else {
+			goto Skip;
+		}
+	}
 
 	if (dev->pm_domain) {
 		info = "noirq power domain ";
@@ -1163,6 +1207,28 @@ static int __device_suspend_noirq(struct
 		goto Complete;
 	}
 
+	/*
+	 * The device may be left suspended during system resume if that is
+	 * preferred by its driver and its wakeup configuration is compatible
+	 * with runtime PM, and it will not be used for resuming any of its
+	 * children or consumers.
+	 */
+	if (dev_pm_test_driver_flags(dev, DPM_FLAG_LEAVE_SUSPENDED) &&
+	    (device_may_wakeup(dev) || !device_can_wakeup(dev)) &&
+	    !dev->power.must_resume) {
+		dpm_leave_suspended(dev);
+		goto Complete;
+	}
+
+	/*
+	 * The parent and suppliers will be necessary to resume the device
+	 * during system resume, so avoid leaving them in runtime suspend.
+	 */
+	if (dev->parent)
+		dev->parent->power.must_resume = true;
+
+	dpm_suppliers_set_must_resume(dev);
+
 Skip:
 	dev->power.is_noirq_suspended = true;
 
@@ -1698,8 +1764,9 @@ static int device_prepare(struct device
 	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,
@@ -1712,6 +1779,12 @@ static int device_prepare(struct device
 	device_lock(dev);
 
 	dev->power.wakeup_path = device_may_wakeup(dev);
+	/*
+	 * Avoid leaving devices in suspend after transitions that don't really
+	 * suspend them in general.
+	 */
+	dev->power.must_resume = state.event == PM_EVENT_FREEZE ||
+				state.event == PM_EVENT_QUIESCE;
 
 	if (dev->power.no_pm_callbacks) {
 		ret = 1;	/* Let device go direct_complete */
Index: linux-pm/Documentation/driver-api/pm/devices.rst
===================================================================
--- linux-pm.orig/Documentation/driver-api/pm/devices.rst
+++ linux-pm/Documentation/driver-api/pm/devices.rst
@@ -785,6 +785,22 @@ means that they should be put into the f
 
 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 may be desirable to leave some devices in runtime suspend after
+system resume and device drivers can use the ``DPM_FLAG_LEAVE_SUSPENDED`` flag
+to indicate to the PM core that this is the case.  If that flag is set for a
+device and the wakeup settings of it are compatible with runtime PM (that is,
+either the device is configured to wake up the system from sleep or it cannot
+generate wakeup signals at all), and it will not be used for resuming any of its
+children or consumers, the PM core will skip all of the system resume callbacks
+in the ``resume_noirq``, ``resume_early`` and ``resume`` phases for it and its
+runtime power management status will be set to "suspended".
+
+Still, if the platform firmware is involved in the handling of system resume, it
+may change the state of devices in unpredictable ways, so in that case the
+middle layer code (for example, a bus type or PM domain) the driver works with
+should update the device's power state and schedule runtime resume of it to
+align its power settings with the expectations of the runtime PM framework.

  parent reply	other threads:[~2017-10-16  1:43 UTC|newest]

Thread overview: 135+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-10-16  1:12 [PATCH 0/12] PM / sleep: Driver flags for system suspend/resume Rafael J. Wysocki
2017-10-16  1:29 ` [PATCH 01/12] PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags Rafael J. Wysocki
2017-10-16  5:34   ` Lukas Wunner
2017-10-16 22:03     ` Rafael J. Wysocki
2017-10-16  6:28   ` Greg Kroah-Hartman
2017-10-16 22:05     ` Rafael J. Wysocki
2017-10-17  7:15       ` Greg Kroah-Hartman
2017-10-17 15:26         ` Rafael J. Wysocki
2017-10-18  6:56           ` Greg Kroah-Hartman
2017-10-16  6:31   ` Greg Kroah-Hartman
2017-10-16 22:07     ` Rafael J. Wysocki
2017-10-17 13:26       ` Greg Kroah-Hartman
2017-10-16 20:16   ` Alan Stern
2017-10-16 22:11     ` Rafael J. Wysocki
2017-10-18 23:17   ` [Update][PATCH v2 " Rafael J. Wysocki
2017-10-19  7:33     ` Greg Kroah-Hartman
2017-10-20 11:11       ` Rafael J. Wysocki
2017-10-20 11:35         ` Greg Kroah-Hartman
2017-10-20 11:28           ` Rafael J. Wysocki
2017-10-23 16:37     ` Ulf Hansson
2017-10-23 20:41       ` Rafael J. Wysocki
2017-10-16  1:29 ` [PATCH 02/12] PCI / PM: Use the NEVER_SKIP driver flag Rafael J. Wysocki
2017-10-23 16:40   ` Ulf Hansson
2017-10-16  1:29 ` [PATCH 03/12] PM: i2c-designware-platdrv: Use DPM_FLAG_SMART_PREPARE Rafael J. Wysocki
2017-10-23 16:57   ` Ulf Hansson
2017-10-16  1:29 ` [PATCH 04/12] PM / core: Add SMART_SUSPEND driver flag Rafael J. Wysocki
2017-10-23 19:01   ` Ulf Hansson
2017-10-24  5:22   ` Ulf Hansson
2017-10-24  8:55     ` Rafael J. Wysocki
2017-10-16  1:29 ` [PATCH 05/12] PCI / PM: Drop unnecessary invocations of pcibios_pm_ops callbacks Rafael J. Wysocki
2017-10-23 19:06   ` Ulf Hansson
2017-10-16  1:29 ` [PATCH 06/12] PCI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-16  1:29 ` [PATCH 07/12] ACPI / LPSS: Consolidate runtime PM and system sleep handling Rafael J. Wysocki
2017-10-23 19:09   ` Ulf Hansson
2017-10-16  1:30 ` [PATCH 08/12] ACPI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-16  1:30 ` [PATCH 09/12] PM / mfd: intel-lpss: Use DPM_FLAG_SMART_SUSPEND Rafael J. Wysocki
2017-10-31 15:09   ` Lee Jones
2017-10-31 16:28     ` Rafael J. Wysocki
2017-11-01  9:28       ` Lee Jones
2017-11-01 20:26         ` Rafael J. Wysocki
2017-11-08 11:08           ` Lee Jones
2017-10-16  1:30 ` Rafael J. Wysocki [this message]
2017-10-23 19:38   ` [PATCH 10/12] PM / core: Add LEAVE_SUSPENDED driver flag Ulf Hansson
2017-10-16  1:31 ` [PATCH 11/12] PM: i2c-designware-platdrv: Optimize power management Rafael J. Wysocki
2017-10-26 20:41   ` Wolfram Sang
2017-10-26 21:14     ` Rafael J. Wysocki
2017-10-16  1:32 ` [PATCH 12/12] PM / core: Add AVOID_RPM driver flag Rafael J. Wysocki
2017-10-17 15:33   ` Andy Shevchenko
2017-10-17 15:59     ` Rafael J. Wysocki
2017-10-17 16:25       ` Andy Shevchenko
2017-10-16  7:08 ` [PATCH 0/12] PM / sleep: Driver flags for system suspend/resume Greg Kroah-Hartman
2017-10-16 21:50   ` Rafael J. Wysocki
2017-10-17  8:36 ` Ulf Hansson
2017-10-17 15:25   ` Rafael J. Wysocki
2017-10-17 19:41     ` Ulf Hansson
2017-10-17 20:12       ` Alan Stern
2017-10-17 23:07         ` Rafael J. Wysocki
2017-10-18  0:39       ` Rafael J. Wysocki
2017-10-18 10:24         ` Rafael J. Wysocki
2017-10-18 12:34           ` Ulf Hansson
2017-10-18 21:54             ` Rafael J. Wysocki
2017-10-18 11:57         ` Ulf Hansson
2017-10-18 13:00           ` Rafael J. Wysocki
2017-10-18 14:11             ` Ulf Hansson
2017-10-18 19:45               ` Grygorii Strashko
2017-10-18 21:48                 ` Rafael J. Wysocki
2017-10-19  8:33                   ` Ulf Hansson
2017-10-19 17:21                     ` Grygorii Strashko
2017-10-19 18:04                       ` Ulf Hansson
2017-10-19 18:11                         ` Ulf Hansson
2017-10-19 21:31                           ` Grygorii Strashko
2017-10-20  6:05                             ` Ulf Hansson
2017-10-18 22:12               ` Rafael J. Wysocki
2017-10-19 12:21                 ` Ulf Hansson
2017-10-19 18:01                   ` Ulf Hansson
2017-10-20  1:19                   ` Rafael J. Wysocki
2017-10-20  5:57                     ` Ulf Hansson
2017-10-20 20:46 ` Bjorn Helgaas
2017-10-21  1:04   ` Rafael J. Wysocki
2017-10-27 22:11 ` [PATCH v2 0/6] PM / sleep: Driver flags for system suspend/resume (part 1) Rafael J. Wysocki
2017-10-27 22:17   ` [PATCH v2 1/6] PM / core: Add NEVER_SKIP and SMART_PREPARE driver flags Rafael J. Wysocki
2017-11-06  8:07     ` Ulf Hansson
2017-10-27 22:19   ` [PATCH v2 2/6] PCI / PM: Use the NEVER_SKIP driver flag Rafael J. Wysocki
2017-10-27 22:22   ` [PATCH v2 3/6] PM / core: Add SMART_SUSPEND " Rafael J. Wysocki
2017-11-06  8:09     ` Ulf Hansson
2017-11-06 11:23       ` Rafael J. Wysocki
2017-10-27 22:23   ` [PATCH v2 4/6] PCI / PM: Drop unnecessary invocations of pcibios_pm_ops callbacks Rafael J. Wysocki
2017-10-27 22:27   ` [PATCH v2 5/6] PCI / PM: Take SMART_SUSPEND driver flag into account Rafael J. Wysocki
2017-10-31 22:48     ` Bjorn Helgaas
2017-10-27 22:30   ` [PATCH v2 6/6] ACPI " Rafael J. Wysocki
2017-11-08  0:41   ` [PATCH v2 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-08 13:25     ` [PATCH v2 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-10  9:09       ` Ulf Hansson
2017-11-10 23:45         ` Rafael J. Wysocki
2017-11-11  0:41           ` Rafael J. Wysocki
2017-11-11  1:36           ` Rafael J. Wysocki
2017-11-14 16:07           ` Ulf Hansson
2017-11-15  1:48             ` Rafael J. Wysocki
2017-11-16 10:18               ` Ulf Hansson
2017-11-08 13:28     ` [PATCH v2 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-08 20:38       ` Bjorn Helgaas
2017-11-08 21:09         ` Rafael J. Wysocki
2017-11-08 13:34     ` [PATCH v2 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-08 13:37     ` [PATCH v2 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-08 13:38     ` [PATCH v2 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-08 13:39     ` [PATCH v2 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki
2017-11-12  0:34     ` [PATCH v3 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-12  0:37       ` [PATCH v3 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-16 15:10         ` Ulf Hansson
2017-11-16 23:07           ` Rafael J. Wysocki
2017-11-17  6:11             ` Ulf Hansson
2017-11-17 13:18               ` Rafael J. Wysocki
2017-11-17 13:49                 ` Ulf Hansson
2017-11-17 14:31                   ` Rafael J. Wysocki
2017-11-17 15:57                     ` Ulf Hansson
2017-11-17 12:45             ` Rafael J. Wysocki
2017-11-12  0:40       ` [PATCH v3 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-12  0:40       ` [PATCH v3 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-12  0:42       ` [PATCH v3 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-15  7:43         ` Ulf Hansson
2017-11-15 17:55           ` Rafael J. Wysocki
2017-11-12  0:43       ` [PATCH v3 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-12  0:44       ` [PATCH v3 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki
2017-11-18 14:27       ` [PATCH v4 0/6] PM / sleep: Driver flags for system suspend/resume (part 2) Rafael J. Wysocki
2017-11-18 14:31         ` [PATCH v4 1/6] PM / core: Add LEAVE_SUSPENDED driver flag Rafael J. Wysocki
2017-11-20 12:25           ` Ulf Hansson
2017-11-21  0:16             ` Rafael J. Wysocki
2017-11-18 14:33         ` [PATCH v4 2/6] PCI / PM: Support for " Rafael J. Wysocki
2017-11-18 14:35         ` [PATCH v4 3/6] ACPI / PM: Support for LEAVE_SUSPENDED driver flag in ACPI PM domain Rafael J. Wysocki
2017-11-18 14:37         ` [PATCH v4 4/6] PM / core: Add helpers for subsystem callback selection Rafael J. Wysocki
2017-11-18 14:41         ` [PATCH v4 5/6] PM / core: Direct handling of DPM_FLAG_LEAVE_SUSPENDED Rafael J. Wysocki
2017-11-20 13:42           ` Ulf Hansson
2017-11-22  1:10             ` Rafael J. Wysocki
2017-11-22  1:28               ` Rafael J. Wysocki
2017-11-18 14:44         ` [PATCH v4 6/6] PM / core: DPM_FLAG_SMART_SUSPEND optimization Rafael J. Wysocki

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