From: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Date: Thu, 29 Sep 2016 12:36:36 +0000 (+0200)
Subject: PM / devfreq: Skip status update on uninitialized previous_freq
X-Git-Tag: v4.9-rc1~19^2^3
X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=d0563a039c9d35305f4cb2405665130de596d86a

PM / devfreq: Skip status update on uninitialized previous_freq

In case devfreq->previous_freq is still uninitialized in
devfreq_update_status(), i.e. it has value '0', the lookups in
that function fail, eventually leading to some error message:
[    3.041292] devfreq bus_dmc: Couldn't update frequency transition information.

Just skip the statup update in this situation.

Signed-off-by: Tobias Jakobi <tjakobi@math.uni-bielefeld.de>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 66d3c7184a0f..bf3ea7603a58 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -137,6 +137,10 @@ static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
 
 	cur_time = jiffies;
 
+	/* Immediately exit if previous_freq is not initialized yet. */
+	if (!devfreq->previous_freq)
+		goto out;
+
 	prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
 	if (prev_lev < 0) {
 		ret = prev_lev;