On 09/18/2013 08:48 PM, Soren Brinkmann wrote: > On most ARM systems the per-cpu clockevents are truly per-cpu in > the sense that they can't be controlled on any other CPU besides > the CPU that they interrupt. If one of these clockevents were to > become a broadcast source we will run into a lot of trouble > because the broadcast source is enabled on the first CPU to go > into deep idle (if that CPU suffers from FEAT_C3_STOP) and that > could be a different CPU than what the clockevent is interrupting > (or even worse the CPU that the clockevent interrupts could be > offline). > > Theoretically it's possible to support per-cpu clockevents as the > broadcast source but so far we haven't needed this and supporting > it is rather complicated. Let's just deny the possibility for now > until this becomes a reality (let's hope it never does!). > > Signed-off-by: Soren Brinkmann <[email protected]>
Acked-by: Daniel Lezcano <[email protected]> > --- > kernel/time/tick-broadcast.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c > index 218bcb5..9532690 100644 > --- a/kernel/time/tick-broadcast.c > +++ b/kernel/time/tick-broadcast.c > @@ -70,6 +70,7 @@ static bool tick_check_broadcast_device(struct > clock_event_device *curdev, > struct clock_event_device *newdev) > { > if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) || > + (newdev->features & CLOCK_EVT_FEAT_PERCPU) || > (newdev->features & CLOCK_EVT_FEAT_C3STOP)) > return false; > > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
