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

[Rafael J. Wysocki]

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

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.wyso...@intel.com>
---
 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;