tick_oneshot_notify() is used to notify a particular CPU to try to switch into oneshot mode after a oneshot capable tick device is registered and tick_clock_notify() is used to notify all CPUs to try to switch into oneshot mode after a high res clocksource is registered. There is one caveat; if the tick devices suffer from FEAT_C3_STOP we don't try to switch into oneshot mode unless we have a oneshot capable broadcast device already registered. If the broadcast device is registered after the tick devices that have FEAT_C3_STOP we'll never try to switch into oneshot mode again, causing us to be stuck in periodic mode forever. Avoid this scenario by calling tick_clock_notify() after we register the broadcast device so that we try to switch into oneshot mode on all CPUs one more time. Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> --- Found this one when we were registering our broadcast timer after irqs were enabled. We've moved the registration before the irqs are enabled now so technically we don't need this patch anymore, but it seemed like a good idea to fix it in the core anyway to save someone else the trouble of tracking it down later. kernel/time/tick-broadcast.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index 7f32fe0..69b1b1a 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -77,6 +77,8 @@ int tick_check_broadcast_device(struct clock_event_device *dev) tick_broadcast_device.evtdev = dev; if (!cpumask_empty(tick_get_broadcast_mask())) tick_broadcast_start_periodic(dev); + if (dev->features & CLOCK_EVT_FEAT_ONESHOT) + tick_clock_notify(); return 1; } -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
