[PATCH 4/4] PM / sleep: Check pm_wakeup_pending() in __device_suspend_noirq()

[Rafael J. Wysocki]

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

Restore the pm_wakeup_pending() check in __device_suspend_noirq()
removed by commit eed4d47efe95 (ACPI / sleep: Ignore spurious SCI
wakeups from suspend-to-idle) as that allows the function to return
earlier if there's a wakeup event pending already (so that it may
spend less time on carrying out operations that will be reversed
shortly anyway) and rework the main suspend-to-idle loop to take
that optimization into account.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
 drivers/base/power/main.c |    5 +++++
 kernel/power/suspend.c    |   19 ++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

Index: linux-pm/kernel/power/suspend.c
===================================================================
--- linux-pm.orig/kernel/power/suspend.c
+++ linux-pm/kernel/power/suspend.c
@@ -106,19 +106,32 @@ static void s2idle_loop(void)
 {
 	pm_pr_dbg("suspend-to-idle\n");
 
-	while (!dpm_suspend_noirq(PMSG_SUSPEND)) {
+	for (;;) {
+		int error;
+
+		dpm_noirq_begin();
+
 		/*
 		 * Suspend-to-idle equals
 		 * frozen processes + suspended devices + idle processors.
 		 * Thus freeze_enter() should be called right after
 		 * all devices have been suspended.
 		 */
-		freeze_enter();
+		error = dpm_noirq_suspend_devices(PMSG_SUSPEND);
+		if (!error)
+			freeze_enter();
+
+		dpm_noirq_resume_devices(PMSG_RESUME);
+		if (error && (error != -EBUSY || !pm_wakeup_pending())) {
+			dpm_noirq_end();
+			break;
+		}
 
 		if (freeze_ops && freeze_ops->wake)
 			freeze_ops->wake();
 
-		dpm_resume_noirq(PMSG_RESUME);
+		dpm_noirq_end();
+
 		if (freeze_ops && freeze_ops->sync)
 			freeze_ops->sync();
 
Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -1105,6 +1105,11 @@ static int __device_suspend_noirq(struct
 	if (async_error)
 		goto Complete;
 
+	if (pm_wakeup_pending()) {
+		async_error = -EBUSY;
+		goto Complete;
+	}
+
 	if (dev->power.syscore || dev->power.direct_complete)
 		goto Complete;