linux-kernel - [PATCH 3.16 293/328] PM / core: Clear the direct

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Date:   Sun, 09 Dec 2018 21:50:33 +0000
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "Al Cooper" <alcooperx@...il.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        "Ulf Hansson" <ulf.hansson@...aro.org>
Subject: [PATCH 3.16 293/328] PM / core: Clear the direct_complete flag on
 errors

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

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

commit 69e445ab8b66a9f30519842ef18be555d3ee9b51 upstream.

If __device_suspend() runs asynchronously (in which case the device
passed to it is in dpm_suspended_list at that point) and it 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 that 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>
Tested-by: Al Cooper <alcooperx@...il.com>
Reviewed-by: Ulf Hansson <ulf.hansson@...aro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 drivers/base/power/main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -1336,8 +1336,10 @@ static int __device_suspend(struct devic

 	dpm_wait_for_children(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
@@ -1349,6 +1351,7 @@ 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;
 	}