From: Tero Kristo Date: Thu, 24 Feb 2011 15:19:23 +0000 (+0200) Subject: cpuidle: menu: fixed wrapping timers at 4.294 seconds X-Git-Url: http://git.alex.org.uk cpuidle: menu: fixed wrapping timers at 4.294 seconds BugLink: http://bugs.launchpad.net/bugs/774947 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: Tero Kristo Signed-off-by: Len Brown (cherry picked from commit 7467571f4480b273007517b26297c07154c73924) Acked-by: Stefan Bader Signed-off-by: Tim Gardner --- diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c index f508690..c47f3d0 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -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);