Re: [Qemu-devel] [PATCH][RFC 0/14] implement power chip

[li guang]

在 2013-03-19二的 10:15 +0000，Peter Maydell写道：
> On 19 March 2013 09:31, li guang <address@hidden> wrote:
> > 在 2013-03-19二的 09:05 +0000，Peter Maydell写道：
> >> I suspect this should involve more modelling of actual
> >> control signals between the power controller and
> >> the devices, not methods on the base class.
> >>
> >
> > do we have to realize something like signals which are actually
> > only some copper wires?
> > I think we just emulate the real work, that is when some signals
> > asserted, we just call corresponding method to do something
> > by these embedded method, I want to let devices take care
> > of power event(on/off/suspend/wakeup) themselves.
> 
> The point is that how exactly power controllers connect
> to devices, and which devices respond to reset/suspend/etc
> is a property of the individual machine being modelled.
> An x86 PC will be different from an ARM devboard which is
> different again from the Exynos4 ARM SoC. So to allow this
> flexibility, you have to let the machine model do the configuration,
> which you do by having the model wire up the power controller
> to the devices in the same way it's done on hardware.

agree, originally, I  made all devices can realize the power 
state callbacks, e.g. if one can do suspend, then it will
realize DeviceState::suspend, so if system go to suspend,
this method will be called.
do you want some explicit way to configure for machine's 
devices if they can support power state changes?

> 
> >> > I'm eager to get more comments and discussion.
> >> > This idea simply based on system board design convention,
> >> > I'm not saying a power chip has signals directly connected
> >> > to all devices, I mean system board and its devices should
> >> > have protocol to deal with power state changes.
> >>
> >> Hardware does it with signals, so should we.
> >
> > can these signals be viewed as the calling of corresponding methods?
> 
> In some ways, they are -- but the wiring up of the source of
> the call to the implementation is done at runtime as devices
> are connected together.

So, can I go ahead to do this work?

Thanks!

Li Guang