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Re: [Qemu-devel] Register uhci_reset() callback.
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] Register uhci_reset() callback. |
Date: |
Tue, 16 Jun 2009 22:10:59 +0300 |
On 6/16/09, Jamie Lokier <address@hidden> wrote:
> Jamie Lokier wrote:
>
> > Blue Swirl wrote:
> > It's analogous to a distributed atomic transaction problem.
I did not wrote this, it was you.
> >
> > So you need two phases:
> >
> > - Restoring: All devices states are restored, one by one including
> > output levels of interrupt lines and GPIOs, but nothing actually
> > _happens_ when those levels are set.
> >
> > - Running: All devices start running at the same instant from
> > their restored state. They don't need to reexamine input
> > levels, because their internal states are already consistent
> > with the input levels.
> >
> > In the restoring phase, you might still use the normal functions to
> > set output levels, but they would be prevented from being passed as
> > changes to other devices.
> >
> > Anything else might be made to work with particular PICs etc., but
> > two-phase restore is what you need to work with any wiring (including
> > cycles) of arbitrary devices with arbitrary states.
>
>
> I should say, the above applies to both restoring saved state, and
> whole system resets.
>
> That's why real hardware has a nice long reset pulse, during which
> every input change is ignored until the reset pulse is removed.
qemu_irq does not have state. It's different from real HW IRQ, so QEMU
devices don't need to do anything. I also had this confused earlier.
- Re: [Qemu-devel] Register uhci_reset() callback., (continued)
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Jamie Lokier, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Jamie Lokier, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback.,
Blue Swirl <=
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16