linux-kernel - [PATCH 18/70] cpufreq: interactive: keep freezer happy when not current governor

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Date:	Tue, 27 Oct 2015 18:30:06 +0100
From:	Bálint Czobor <czoborbalint@...il.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Sam Leffler <sleffler@...omium.org>,
	Bálint Czobor <czoborbalint@...il.com>
Subject: [PATCH 18/70] cpufreq: interactive: keep freezer happy when not current governor

From: Sam Leffler <sleffler@...omium.org>

Fix a problem where the hung task mechanism was deeming the interactive
clock boost thread as hung.  This was because the thread is created at
module init but never run/woken up until needed.  If the governor is not
being used this can be forever.  To workaround this explicitly wake up
the thread once all the necessary data structures are initialized.  The
latter required some minor code shuffle.

Signed-off-by: Sam Leffler <sleffler@...omium.org>
Change-Id: Ie2c058dd75dcb6460ea10e7ac997e46baf66b1fe
Signed-off-by: Bálint Czobor <czoborbalint@...il.com>
---
 drivers/cpufreq/cpufreq_interactive.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 2038991..184140a 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -953,6 +953,10 @@ static int __init cpufreq_interactive_init(void)
 		pcpu->cpu_timer.data = i;
 	}
 
+	spin_lock_init(&up_cpumask_lock);
+	spin_lock_init(&down_cpumask_lock);
+	mutex_init(&set_speed_lock);
+
 	up_task = kthread_create(cpufreq_interactive_up_task, NULL,
 				 "kinteractiveup");
 	if (IS_ERR(up_task))
@@ -968,14 +972,12 @@ static int __init cpufreq_interactive_init(void)
 	if (!down_wq)
 		goto err_freeuptask;
 
-	INIT_WORK(&freq_scale_down_work,
-		  cpufreq_interactive_freq_down);
+	INIT_WORK(&freq_scale_down_work, cpufreq_interactive_freq_down);
+	INIT_WORK(&inputopen.inputopen_work, cpufreq_interactive_input_open);
 
-	spin_lock_init(&up_cpumask_lock);
-	spin_lock_init(&down_cpumask_lock);
-	mutex_init(&set_speed_lock);
+	/* NB: wake up so the thread does not look hung to the freezer */
+	wake_up_process(up_task);
 
-	INIT_WORK(&inputopen.inputopen_work, cpufreq_interactive_input_open);
 	return cpufreq_register_governor(&cpufreq_gov_interactive);
 
 err_freeuptask:
-- 
1.7.9.5

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