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From: Dmitry Osipenko <digetx@gmail.com>
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>
Subject: Re: [Qemu-arm] [PATCH v10 2/7] hw/ptimer: Perform tick and counter wrap around if timer already expired
Date: Wed, 20 Jan 2016 20:03:47 +0300	[thread overview]
Message-ID: <569FBDF3.2070405@gmail.com> (raw)
In-Reply-To: <CAPokK=qC77XBkNpHa1y_Dajd9Hv8+a-wx9iqC1dRumeKgvUvaA@mail.gmail.com>

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

  parent reply	other threads:[~2016-01-20 17:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-09 17:39 [Qemu-devel] [PATCH v10 0/7] PTimer fixes/features and ARM MPTimer conversion Dmitry Osipenko
2016-01-09 17:39 ` [Qemu-devel] [PATCH v10 1/7] hw/ptimer: Fix issues caused by the adjusted timer limit value Dmitry Osipenko
2016-01-10  0:28   ` [Qemu-arm] " Peter Crosthwaite
2016-01-09 17:39 ` [Qemu-devel] [PATCH v10 2/7] hw/ptimer: Perform tick and counter wrap around if timer already expired Dmitry Osipenko
2016-01-10  0:44   ` [Qemu-arm] " Peter Crosthwaite
2016-01-10 14:09     ` Dmitry Osipenko
2016-01-20 17:03     ` Dmitry Osipenko [this message]
2016-01-20 17:22       ` [Qemu-devel] " Dmitry Osipenko
2016-01-09 17:39 ` [Qemu-devel] [PATCH v10 3/7] hw/ptimer: Update .delta on period/freq change Dmitry Osipenko
2016-01-09 17:39 ` [Qemu-arm] [PATCH v10 4/7] hw/ptimer: Support "on the fly" timer mode switch Dmitry Osipenko
2016-01-10  0:50   ` Peter Crosthwaite
2016-01-09 17:39 ` [Qemu-devel] [PATCH v10 5/7] hw/ptimer: Legalize running with delta = load = 0 Dmitry Osipenko
2016-01-12  3:58   ` [Qemu-arm] " Peter Crosthwaite
2016-01-12 18:12     ` Dmitry Osipenko
2016-01-15 18:10       ` Dmitry Osipenko
2016-01-20  0:50       ` Dmitry Osipenko
2016-01-09 17:39 ` [Qemu-arm] [PATCH v10 6/7] hw/ptimer: Introduce ptimer_get_limit Dmitry Osipenko
2016-01-12  3:59   ` [Qemu-devel] " Peter Crosthwaite
2016-01-09 17:39 ` [Qemu-arm] [PATCH v10 7/7] arm_mptimer: Convert to use ptimer Dmitry Osipenko
2016-01-10 18:05   ` Dmitry Osipenko
2016-01-10 18:12     ` Dmitry Osipenko

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