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From: Dmitry Osipenko <digetx@gmail.com>
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Date: Wed, 20 Jan 2016 20:03:47 +0300
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Subject: Re: [Qemu-devel] [PATCH v10 2/7] hw/ptimer: Perform tick and
 counter wrap around if timer already expired
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To: Peter Crosthwaite <crosthwaitepeter@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, qemu-arm <qemu-arm@nongnu.org>, QEMU Developers <qemu-devel@nongnu.org>

Hi Peter,

10.01.2016 03:44, Peter Crosthwaite пишет:
> On Sat, Jan 9, 2016 at 9:39 AM, Dmitry Osipenko <digetx@gmail.com> wrote:
[cut]
>> In addition, there is no reason to keep expired timer tick deferred, so
>> just perform the tick from ptimer_get_count().
>>
[cut]

I noticed an issue here... The problem is that device reset invokes 
ptimer_stop() that invokes ptimer_get_count() that might cause the tick after 
reset, i.e. bogus bh would be invoked after QEMU reset. I have reproduced that 
issue.

The solution might be to introduce ptimer_reset() that would stop QEMU timer and 
reset delta/load/period without invoking ptimer_get_count. And of course all 
devices should be updated to use new ptimer_reset() prior to "Perform tick and 
counter wrap around if timer already expired" patch, but that's not an issue I 
suppose. Please let me know if you have any objections, I'm leaning to do it in V11.

void ptimer_reset(ptimer_state *s)
{
     timer_del(s->timer);
     s->enabled = 0;
     s->period_frac = 0;
     s->period = 0;
     s->delta = 0;
     s->limit = 0;
}

-- 
Dmitry