• Prasad Sodagudi's avatar
    clockevents: Update clockevents device next_event on stop · 39c82caf
    Prasad Sodagudi authored
    clockevent_device::next_event holds the next timer event of a clock event
    device. The value is updated in clockevents_program_event(), i.e. when the
    hardware timer is armed for the next expiry.
    When there are no software timers armed on a CPU, the corresponding per CPU
    clockevent device is brought into ONESHOT_STOPPED state, but
    clockevent_device::next_event is not updated, because
    clockevents_program_event() is not called.
    So the content of clockevent_device::next_event is stale, which is not an
    issue when real hardware is used. But the hrtimer broadcast device relies
    on that information and the stale value causes spurious wakeups.
    Update clockevent_device::next_event to KTIME_MAX when it has been brought
    into ONESHOT_STOPPED state to avoid spurious wakeups. This reflects the
    proper expiry time of the stopped timer: infinity.
    [ tglx: Massaged changelog ]
    Signed-off-by: default avatarPrasad Sodagudi <psodagud@codeaurora.org>
    Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
    Cc: viresh.kumar@linaro.org
    Link: https://lkml.kernel.org/r/1509043042-32486-1-git-send-email-psodagud@codeaurora.org
tick-oneshot.c 3.27 KB