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    Subject[PATCH 01/18] cpuidle: menu: fixed wrapping timers at 4.294 seconds
    Date
    From: Tero Kristo <tero.kristo@nokia.com>

    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
    Signed-off-by: Tero Kristo <tero.kristo@nokia.com>
    Signed-off-by: Len Brown <len.brown@intel.com>
    ---
    drivers/cpuidle/governors/menu.c | 4 +++-
    1 files changed, 3 insertions(+), 1 deletions(-)

    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);
    --
    1.7.5.rc0


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