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clockevents: Stop unused clockevent devices
authorViresh Kumar <viresh.kumar@linaro.org>
Fri, 3 Apr 2015 03:34:05 +0000 (09:04 +0530)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 19 May 2015 14:18:11 +0000 (16:18 +0200)
commitd25408756accbd2171abaa0678f986adae139e6f
tree151e54ed16e45ab33ede5b9896b88a28f99fc164
parent8fff52fd50934580c5108afed12043a774edf728
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>
kernel/time/clockevents.c
kernel/time/hrtimer.c
kernel/time/tick-oneshot.c