linux-kernel - [PATCH 4.9 08/35] PM / core: Clear the direct

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Date:   Thu, 11 Oct 2018 17:35:10 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Al Cooper <alcooperx@...il.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
Subject: [PATCH 4.9 08/35] PM / core: Clear the direct_complete flag on errors

4.9-stable 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>
Cc: 3.16+ <stable@...r.kernel.org> # 3.16+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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
@@ -1360,8 +1360,10 @@ 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
@@ -1373,6 +1375,7 @@ 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;
 	}