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Re: [Qemu-arm] [PATCH v14 1/3] hw/ptimer: Support running with counter =

From: Peter Maydell
Subject: Re: [Qemu-arm] [PATCH v14 1/3] hw/ptimer: Support running with counter = 0 by introducing new policy feature
Date: Thu, 23 Jun 2016 17:43:55 +0100

On 23 June 2016 at 17:32, Dmitry Osipenko <address@hidden> wrote:
> On 23.06.2016 16:49, Peter Maydell wrote:
>> On 17 June 2016 at 14:17, Dmitry Osipenko <address@hidden> wrote:
>>> Currently ptimer prints error message and stops the running timer that has
>>> delta (counter) = 0, this is an incorrect behaviour for some of the ptimer
>>> users. There are different variants of how particular timer could handle 
>>> that
>>> case besides stopping the timer, like immediate or deferred IRQ trigger.
>>> Introduce policy feature that provides ptimer with an information about the
>>> correct behaviour.
>>> Implement the "counter = 0 triggers IRQ after one period" policy, as it is
>>> known to be used by the ARM MPTimer and set "default" policy to all ptimer
>>> users, maintaining old behaviour till they get fixed.
>> Could you split this into:
>>  (1) a patch which just adds the new argument to ptimer_init() and
>>      updates all its callers
>>  (2) a patch which adds support for setting the policy option to
>>      something other than the default value
>> and also make sure that we only do one change per patch -- there
>> seem to be several different behaviour changes tangled up in
>> one patch here.
>> I think that will be easier to review.
> This patch isn't supposed to change behaviour for any of the current timers. I
> think it is clearly expressed in the last sentence of the commit message. 
> There
> is one unintended behaviour change in this patch, it's my overlook [see 
> below].

Right, but my point is that it is hard to tell that when I read
the patch to review it, and splitting this will make it easier.

-- PMM

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