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

[Peter Maydell]

On 13 March 2013 08:01, liguang <address@hidden> wrote:
> By now, all devices of QEMU do not have much more
> power management consideration, for example, if
> system do suspend, it will call all registered notifiers,
> this was loosely required, and the code to do power management
> state transition seems just do 'ugly emulation', rather than be
> conscious with whole system devices, same condition with reset(it
> has been embedded in DeviceClass, good!),
> shutdown, in real world, commonly all devices' power are controlled
> by a power chip, then all power sequence can be done just
> issue commands to this chip.
> so, I come across an idea to implement qdev'ed power device, and
> make all qdev struct of devices aware of self power management(add
> on/off/wakeup/suspend ... filed for DeviceClass), this will
> bring tidy power management, and the emulation will more like what
> happened in real world.

I'm really dubious that this can or should be implemented by
adding methods at the device base class level. I don't think
real hardware works this way. You could probably do power on/off
like this. Reset definitely shouldn't be done this way, and
suspend probably not either.

I think more documentation/discussion of what you think the
semantics of the power down/up/etc should be might be useful.

thanks
-- PMM