[PATCH 4.9 032/153] hwmon: (it87) Ensure that pwm control cache is current before updating values

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Guenter Roeck <linux@xxxxxxxxxxxx>

commit 82dbe987b70042b340f851bdc969a971081e5f02 upstream.

If sensor attributes were never read, the pwm control data has not been
initiialized, which can cause wrong driver behavior. Ensure that cached
data is current before acting on it.

Reported-by: Kevin Folz <kfolz@xxxxxxxxxx>
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/hwmon/it87.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -1354,6 +1354,7 @@ static ssize_t set_pwm(struct device *de
 		return -EINVAL;
 
 	mutex_lock(&data->update_lock);
+	it87_update_pwm_ctrl(data, nr);
 	if (has_newer_autopwm(data)) {
 		/*
 		 * If we are in automatic mode, the PWM duty cycle register
@@ -1466,6 +1467,7 @@ static ssize_t set_pwm_temp_map(struct d
 	}
 
 	mutex_lock(&data->update_lock);
+	it87_update_pwm_ctrl(data, nr);
 	data->pwm_temp_map[nr] = reg;
 	/*
 	 * If we are in automatic mode, write the temp mapping immediately;