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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Linux PM <linux-pm@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>, Ulf Hansson <ulf.hansson@linaro.org>, Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Subject: [PATCH v1 07/12] PM: sleep: stats: Call dpm_save_failed_step() at most once per phase
Date: Mon, 22 Jan 2024 12:32:46 +0100
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From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

If the handling of two or more devices fails in one suspend-resume
phase, it should be counted once in the statistics which is not
guaranteed to happen during system-wide resume of devices due to
the possible asynchronous execution of device callbacks.

Address this by using the async_error static variable during system-wide
device resume to indicate that there has been a device resume error and
the given suspend-resume phase should be counted as failing.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/main.c |   20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/base/power/main.c
===================================================================
--- linux-pm.orig/drivers/base/power/main.c
+++ linux-pm/drivers/base/power/main.c
@@ -685,7 +685,7 @@ Out:
 	TRACE_RESUME(error);
 
 	if (error) {
-		dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
+		async_error = error;
 		dpm_save_failed_dev(dev_name(dev));
 		pm_dev_err(dev, state, async ? " async noirq" : " noirq", error);
 	}
@@ -705,6 +705,9 @@ static void dpm_noirq_resume_devices(pm_
 	ktime_t starttime = ktime_get();
 
 	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, true);
+
+	async_error = 0;
+
 	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
 
@@ -734,6 +737,9 @@ static void dpm_noirq_resume_devices(pm_
 	mutex_unlock(&dpm_list_mtx);
 	async_synchronize_full();
 	dpm_show_time(starttime, state, 0, "noirq");
+	if (async_error)
+		dpm_save_failed_step(SUSPEND_RESUME_NOIRQ);
+
 	trace_suspend_resume(TPS("dpm_resume_noirq"), state.event, false);
 }
 
@@ -815,7 +821,7 @@ Out:
 	complete_all(&dev->power.completion);
 
 	if (error) {
-		dpm_save_failed_step(SUSPEND_RESUME_EARLY);
+		async_error = error;
 		dpm_save_failed_dev(dev_name(dev));
 		pm_dev_err(dev, state, async ? " async early" : " early", error);
 	}
@@ -839,6 +845,9 @@ void dpm_resume_early(pm_message_t state
 	ktime_t starttime = ktime_get();
 
 	trace_suspend_resume(TPS("dpm_resume_early"), state.event, true);
+
+	async_error = 0;
+
 	mutex_lock(&dpm_list_mtx);
 	pm_transition = state;
 
@@ -868,6 +877,9 @@ void dpm_resume_early(pm_message_t state
 	mutex_unlock(&dpm_list_mtx);
 	async_synchronize_full();
 	dpm_show_time(starttime, state, 0, "early");
+	if (async_error)
+		dpm_save_failed_step(SUSPEND_RESUME_EARLY);
+
 	trace_suspend_resume(TPS("dpm_resume_early"), state.event, false);
 }
 
@@ -971,7 +983,7 @@ static void device_resume(struct device
 	TRACE_RESUME(error);
 
 	if (error) {
-		dpm_save_failed_step(SUSPEND_RESUME);
+		async_error = error;
 		dpm_save_failed_dev(dev_name(dev));
 		pm_dev_err(dev, state, async ? " async" : "", error);
 	}
@@ -1030,6 +1042,8 @@ void dpm_resume(pm_message_t state)
 	mutex_unlock(&dpm_list_mtx);
 	async_synchronize_full();
 	dpm_show_time(starttime, state, 0, NULL);
+	if (async_error)
+		dpm_save_failed_step(SUSPEND_RESUME);
 
 	cpufreq_resume();
 	devfreq_resume();