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| author | Stephen Boyd <sboyd@codeaurora.org> | 2013-04-17 10:26:06 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2013-04-17 21:30:56 +0200 |
| commit | c038c1c44179c80da6201f91ef354e48d5689617 (patch) | |
| tree | a1ee34eadd567393cbdb6632ad7b8abb4a2fc4ea /kernel | |
| parent | b3956a896ea57f25cacd74708b8fab611543a81d (diff) | |
| download | op-kernel-dev-c038c1c44179c80da6201f91ef354e48d5689617.zip op-kernel-dev-c038c1c44179c80da6201f91ef354e48d5689617.tar.gz | |
clockevents: Switch into oneshot mode even if broadcast registered late
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.
[ tglx: Adopted to timers/core and added a comment ]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Link: http://lkml.kernel.org/r/1366219566-29783-1-git-send-email-sboyd@codeaurora.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/time/tick-broadcast.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index d76d816..f8d2109 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -75,6 +75,16 @@ int tick_check_broadcast_device(struct clock_event_device *dev) tick_broadcast_device.evtdev = dev; if (!cpumask_empty(tick_broadcast_mask)) tick_broadcast_start_periodic(dev); + /* + * Inform all cpus about this. We might be in a situation + * where we did not switch to oneshot mode because the per cpu + * devices are affected by CLOCK_EVT_FEAT_C3STOP and the lack + * of a oneshot capable broadcast device. Without that + * notification the systems stays stuck in periodic mode + * forever. + */ + if (dev->features & CLOCK_EVT_FEAT_ONESHOT) + tick_clock_notify(); return 1; } |
