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Commit 7467571f authored by Tero Kristo's avatar Tero Kristo Committed by Len Brown
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cpuidle: menu: fixed wrapping timers at 4.294 seconds 



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.

cc: stable@kernel.org # .32.x through .39.x
Signed-off-by: default avatarTero Kristo <tero.kristo@nokia.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent 521cb40b

drivers/cpuidle/governors/menu.c

+3 −1
Original line number Diff line number Diff line
@@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_device *dev) 
	unsigned int power_usage = -1;

	int i;

	int multiplier;

	struct timespec t;



	if (data->needs_update) {

		menu_update(dev);
@@ -251,8 +252,9 @@ 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);