Re: [Qemu-devel] [PATCH v2] arm_mptimer: Fix timer shutdown

[Peter Maydell <peter.maydell@linaro.org>]

On 2 July 2015 at 18:52, Dmitry Osipenko <digetx@gmail.com> wrote:
> 02.07.2015 20:34, Peter Maydell пишет:
>>
>>
>> This will now cause us to do the "reload the timer"
>> logic if you write a 1 to the control bit when it was
>> already 1, which we didn't do before.
>>
>> The logic I suggested in my previous review
>> comment gets this right...
>>
>> -- PMM
>>
>
> The problem with code you suggested is that won't start periodic count after
> one-shot tick was completed.

Can you give more detail? This code is only for when
the guest writes to the control register, so it doesn't
get run when a one-shot tick completes.

In any case, the code currently in master does:
  old value   new value    action
      0           0          nothing
      0           1          reload timer
      1           0          nothing
      1           1          nothing

Your first patch did:

  old value   new value    action
      0           0          delete timer
      0           1          reload timer
      1           0          delete timer
      1           1          nothing

Your second patch does:

  old value   new value    action
      0           0          nothing
      0           1          reload timer
      1           0          delete timer
      1           1          reload timer

My suggestion was:

  old value   new value    action
      0           0          nothing
      0           1          reload timer
      1           0          delete timer
      1           1          nothing

If you think that's wrong, then surely your first
patch also has the same problem?

thanks
-- PMM