From: Tero Kristo <tero.kristo@nokia.com>
Date: Thu, 24 Feb 2011 15:19:23 +0000 (+0200)
Subject: cpuidle: menu: fixed wrapping timers at 4.294 seconds
X-Git-Tag: firefly_0821_release~10164^2~6^2~51
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=af73c7b853bbfd629e1cf02bb6df1c78fd4f1bd1;p=firefly-linux-kernel-4.4.55.git

cpuidle: menu: fixed wrapping timers at 4.294 seconds

commit 7467571f4480b273007517b26297c07154c73924 upstream.

Cpuidle menu governor is using u32 as a temporary datatype for storing
nanosecond values which wrap around at 4.294 seconds. This causes errors
in predicted sleep times resulting in higher than should be C state
selection and increased power consumption. This also breaks cpuidle
state residency statistics.

Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index f8e57c6303f2..053743780baa 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -185,6 +185,7 @@ static int menu_select(struct cpuidle_device *dev)
 	int latency_req = pm_qos_requirement(PM_QOS_CPU_DMA_LATENCY);
 	int i;
 	int multiplier;
+	struct timespec t;
 
 	if (data->needs_update) {
 		menu_update(dev);
@@ -199,8 +200,9 @@ static int menu_select(struct cpuidle_device *dev)
 		return 0;
 
 	/* determine the expected residency time, round up */
+	t = ktime_to_timespec(tick_nohz_get_sleep_length());
 	data->expected_us =
-	    DIV_ROUND_UP((u32)ktime_to_ns(tick_nohz_get_sleep_length()), 1000);
+		t.tv_sec * USEC_PER_SEC + t.tv_nsec / NSEC_PER_USEC;
 
 
 	data->bucket = which_bucket(data->expected_us);