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Re: [Qemu-devel] Register uhci_reset() callback.
From: |
Jamie Lokier |
Subject: |
Re: [Qemu-devel] Register uhci_reset() callback. |
Date: |
Tue, 16 Jun 2009 20:05:29 +0100 |
User-agent: |
Mutt/1.5.13 (2006-08-11) |
Jamie Lokier wrote:
> Blue Swirl wrote:
> It's analogous to a distributed atomic transaction problem.
>
> 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.
-- Jamie
- Re: [Qemu-devel] Register uhci_reset() callback., (continued)
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Avi Kivity, 2009/06/18
- 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 <=
- Re: [Qemu-devel] Register uhci_reset() callback., Blue Swirl, 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
- Re: [Qemu-devel] Register uhci_reset() callback., Gleb Natapov, 2009/06/16
- Re: [Qemu-devel] Register uhci_reset() callback., Paul Brook, 2009/06/16