linux-kernel - [PATCH] PM / core: Clear the direct

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Date:   Thu, 04 Oct 2018 11:08:12 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Al Cooper <alcooperx@...il.com>, Pavel Machek <pavel@....cz>
Subject: [PATCH] PM / core: Clear the direct_complete flag on errors

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

If __device_suspend() returns early on an error or pending wakeup
and the power.direct_complete flag has been set for the device
already, the subsequent device_resume() will be confused by it
and it will call pm_runtime_enable() incorrectly, as runtime PM
has not been disabled for the device by __device_suspend().

To avoid that, clear power.direct_complete if __device_suspend()
is not going to disable runtime PM for the device before returning.

Fixes: aae4518b3124 (PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily)
Reported-by: Al Cooper <alcooperx@...il.com>
Cc: 3.16+ <stable@...r.kernel.org> # 3.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/base/power/main.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -1713,8 +1713,10 @@ static int __device_suspend(struct devic
 
 	dpm_wait_for_subordinate(dev, async);
 
-	if (async_error)
+	if (async_error) {
+		dev->power.direct_complete = false;
 		goto Complete;
+	}
 
 	/*
 	 * If a device configured to wake up the system from sleep states
@@ -1726,6 +1728,7 @@ static int __device_suspend(struct devic
 		pm_wakeup_event(dev, 0);
 
 	if (pm_wakeup_pending()) {
+		dev->power.direct_complete = false;
 		async_error = -EBUSY;
 		goto Complete;
 	}