Re: [Qemu-devel] modelling omap_gpmc with the hierarchical memory API

[Avi Kivity <avi@redhat.com>]

On 08/03/2011 12:06 AM, Anthony Liguori wrote:
>
> The qdev level should be the common base that makes sense for *all* 
> qdev devices.  IRQ management does not belong in DeviceState because 
> what you do for a simple LCD is not what you do for an MSI-X capable 
> PCI device.
>
> This is what QOM properties tries to address.  It should be possible 
> to create a simple device, and register plugs/sockets for GPIO pins 
> without pushing GPIO knowledge into the base class.
>
> In a QDev world, the right approach is to have a GpioDevice base class 
> that implements this sort of logic for devices where it makes sense. 
> That's what SysBusDevice sort of wants to be but it somehow ended up 
> as yet another base class for everything.
>

Doesn't this end up requiring multiple inheritance, and a ton of 
boilerplate in addition?

I'm in favour of throwing everything into qdev so it's easy to use.  If 
a device doesn't have gpio, why, 0 is a valid integer.


-- 
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.