On Thu, Oct 30, 2014 at 06:09:41PM +0000, Lorenzo Pieralisi wrote:

It is done through core code in pci_create_root_bus(), that in turn
calls pci_bus_assign_domain_nr() which is implemented now in pcibios
for arm, it is all in patch 2. What Liviu is saying is correct, it
all

Does request_resources have to be called before pci_create_root_bus
for everything to work right? I didn't trace too deeply, but
pci_create_root_bus is doing all sorts of things with the resource
list.. 

We already know that missing the request_resource causes some subtle
misbehavior in the PCI core...

Also:

+void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent)
+{
+       int domain = of_get_pci_domain_nr(parent->of_node);
+
+       if (domain >= 0) {
+               dt_domain_found = true;
+       } else if (dt_domain_found == true) {
+               dev_err(parent, "Node %s is missing \"linux,pci-domain\" property in DT\n",
+                       parent->of_node->full_name);
+               return;

There isn't any way to return an error from pci_bus_assign_domain_nr,
so I'd think it must always assign something to bus->domain_nr?
Or does higher level code bail out of there are duplicate domains?

Should this error case call pci_get_new_domain_nr() anyhow?

Jason