linux-kernel - [PATCH] PM: sleep: Do not let "syscore" devices runtime-suspend during system transitions

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Date:   Fri, 22 Oct 2021 14:58:23 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PM <linux-pm@...r.kernel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Maulik Shah <mkshah@...eaurora.org>
Subject: [PATCH] PM: sleep: Do not let "syscore" devices runtime-suspend during system transitions

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

There is no reason to allow "syscore" devices to runtime-suspend
during system-wide PM transitions, because they are subject to the
same possible failure modes as any other devices in that respect.

Accordingly, change device_prepare() and device_complete() to call
pm_runtime_get_noresume() and pm_runtime_put(), respectively, for
"syscore" devices too.

Fixes: 057d51a1268f ("Merge branch 'pm-sleep'")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Cc: 3.10+ <stable@...r.kernel.org> # 3.10+
---
 drivers/base/power/main.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -1048,7 +1048,7 @@ static void device_complete(struct devic
 	const char *info = NULL;
 
 	if (dev->power.syscore)
-		return;
+		goto out;
 
 	device_lock(dev);
 
@@ -1078,6 +1078,7 @@ static void device_complete(struct devic
 
 	device_unlock(dev);
 
+out:
 	pm_runtime_put(dev);
 }
 
@@ -1789,9 +1790,6 @@ static int device_prepare(struct device
 	int (*callback)(struct device *) = NULL;
 	int ret = 0;
 
-	if (dev->power.syscore)
-		return 0;
-
 	/*
 	 * If a device's parent goes into runtime suspend at the wrong time,
 	 * it won't be possible to resume the device.  To prevent this we
@@ -1800,6 +1798,9 @@ static int device_prepare(struct device
 	 */
 	pm_runtime_get_noresume(dev);
 
+	if (dev->power.syscore)
+		return 0;
+
 	device_lock(dev);
 
 	dev->power.wakeup_path = false;