Re: [Qemu-devel] [PATCH 11/22] i8259: Update IRQ state after reset

[Jan Kiszka]

On 2011-10-02 21:07, Avi Kivity wrote:
>>>
>>> The way to fix it is two-phase reset:
>>>
>>> phase 1: reset internal state (-> move all outputs to reset
>>> values),
>>> don't sample inputs yet
>>> phase 2: allow sampling inputs
>>
>> As far as I understood Anthony's QOM plans, phase 1 will correspond
>> to
>> "unrealize", phase 2 to "realize".
> 
> That smells of abusing mechanism used for construction for reset purposes.
> 
> Why not use an ordinary qemu_irq?  It reresents a pin; 0->1 edge (assert) 
> enters phase 1, 1->0 edge (deassert) enters phase 2.  Exactly like real 
> hardware.

QEMU makes no difference between power-on reset and system reset right
now. At least I am not aware of any device model that has problems with
this. Thus there is apparently no need to treat reset and create
differently. As QOM requires a two-phase device creation anyway (to let
properties to "settle"), it looks like there is some reuse potential.

Jan

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