Re: [Qemu-devel] [RFC v2 1/4] hw/arm/virt: Allow multiple agents to modify dt

[Peter Maydell]

On 5 January 2015 at 16:14, alvise rigo <address@hidden> wrote:
> On Mon, Jan 5, 2015 at 4:36 PM, Peter Maydell <address@hidden> wrote:
>> Sorry, I think I must have missed this series first time around.
>> I'm not convinced -- I don't see any reason why we should treat
>> the PCI host controller differently from other devices in the
>
> The reason for this is that the PCI host controller needs to generate
> its device node after all the PCI devices have been added to the bus
> (also those specified with the -device option).
> This is required by the interrupt-map node property, that specifies
> for each PCI device an interrupt map entry. Since we have one device
> requiring this 'postponed' node generation, this patch allows also
> other devices to do the same.

What? This doesn't sound right -- you can have hot-plugged PCI
devices, for a start. Device tree is only supposed to be
needed for the bits of hardware that can't be probed, and
we can rely on PCI itself to probe the other devices.

interrupt-map as far as I can tell just specifies how the
interrupt lines are mapped for each PCI slot; it won't
change based on whether devices are present or not. The
example in the wiki:
 http://devicetree.org/Device_Tree_Usage#Advanced_Interrupt_Mapping
cares about number of slots, but that's all.

thanks
-- PMM