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| author | Viresh Kumar <viresh.kumar@linaro.org> | 2015-04-03 09:04:05 +0530 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2015-05-19 16:18:11 +0200 |
| commit | d25408756accbd2171abaa0678f986adae139e6f (patch) | |
| tree | 151e54ed16e45ab33ede5b9896b88a28f99fc164 /kernel/time/clockevents.c | |
| parent | 8fff52fd50934580c5108afed12043a774edf728 (diff) | |
| download | linux-d25408756accbd2171abaa0678f986adae139e6f.tar.bz2 | |
clockevents: Stop unused clockevent devices
To avoid getting spurious interrupts on a tickless CPU, clockevent
device can now be stopped by switching to ONESHOT_STOPPED state.
The natural place for handling this transition is tick_program_event().
On 'expires == KTIME_MAX', we skip programming the event and so we need
to fix such call sites as well, to always call tick_program_event()
irrespective of the expires value.
Once the clockevent device is required again, check if it was earlier
put into ONESHOT_STOPPED state. If yes, switch its state to ONESHOT
before programming its event.
To make sure we haven't missed any corner case, add a WARN() for the
case where we try to reprogram clockevent device while we aren't
configured in ONESHOT_STOPPED state.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5146b07be7f0bc497e0ebae036590ec2fa73e540.1428031396.git.viresh.kumar@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/time/clockevents.c')
| -rw-r--r-- | kernel/time/clockevents.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index dc6afb485027..4922f1b805ea 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -331,6 +331,10 @@ int clockevents_program_event(struct clock_event_device *dev, ktime_t expires, if (dev->state == CLOCK_EVT_STATE_SHUTDOWN) return 0; + /* We must be in ONESHOT state here */ + WARN_ONCE(dev->state != CLOCK_EVT_STATE_ONESHOT, "Current state: %d\n", + dev->state); + /* Shortcut for clockevent devices that can deal with ktime. */ if (dev->features & CLOCK_EVT_FEAT_KTIME) return dev->set_next_ktime(expires, dev); |