Re: [Qemu-devel] [PATCH 21/26] kvmclock: use realize for kvmclock

[Eduardo Habkost]

On Tue, Jun 25, 2013 at 10:20:08AM +0800, Hu Tao wrote:
[...]
> > Is TYPE_SYS_BUS_DEVICE guaranteed to never override ->realize() itself?
> > 
> > From DeviceClass documentation:
> > 
> >  * If a type derived directly from TYPE_DEVICE implements @realize, it does
> >  * not need to implement @init and therefore does not need to store and call
> >  * #DeviceClass' default @realize callback.
> >  * For other types consult the documentation and implementation of the
> >  * respective parent types.
> > 
> > The problem is that there's no documentation about ->realize() on
> > SysBusDeviceClass. Can we please explicitly document SysBusDeviceClass
> > expectations about ->realize() first, before making those changes?
> 
> IIUC, subclass's overriding ->realize should call parent's ->realize at
> some point. Peter Crosthwaite has a patchset to access a object's parent
> class at http://lists.nongnu.org/archive/html/qemu-devel/2013-06/msg02982.html
> 
> Regarding SysBusDevice::init and SysBusDevice::realize, I think it's the
> same as in the case of DeviceClass. If you agree I'll document it as in
> DeviceClass.

I believe it is reasonable to document that SysBusDevice subclasses
don't need to call the parent ->realize() method, like on DeviceClass.
This is exactly what this patch set does, after all, and I haven't seen
anybody complaining about it yet.

-- 
Eduardo