Commit 7467571f authored by Tero Kristo's avatar Tero Kristo Committed by Len Brown

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
...@@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_device *dev) ...@@ -237,6 +237,7 @@ static int menu_select(struct cpuidle_device *dev)
unsigned int power_usage = -1; unsigned int power_usage = -1;
int i; int i;
int multiplier; int multiplier;
struct timespec t;
if (data->needs_update) { if (data->needs_update) {
menu_update(dev); menu_update(dev);
...@@ -251,8 +252,9 @@ static int menu_select(struct cpuidle_device *dev) ...@@ -251,8 +252,9 @@ static int menu_select(struct cpuidle_device *dev)
return 0; return 0;
/* determine the expected residency time, round up */ /* determine the expected residency time, round up */
t = ktime_to_timespec(tick_nohz_get_sleep_length());
data->expected_us = 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); data->bucket = which_bucket(data->expected_us);
......
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