On Mon, 2014-04-07 at 14:44 +0200, Gerd Hoffmann wrote:
Hi,
u8 shpc_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_SHPC);One thing I'd do is maybe check that the relevant memory type is enabled in the bridge (probably just by writing fff to base and reading it back).
This will give hypervisors an option to avoid wasting resources: e.g. it's uncommon for express devices to claim IO.
I don't think we'll need that for the SHPC bridge.
I agree. This is why I chose to check shpc capability, because PCIe ports do not use it (as far as I know).
For express it indeed makes sense to avoid claiming IO address space. I'd try to find something more automatic though, where you don't need some kind of "disable io for this express port" config option.
For express ports which can only have a single device underneath we can check whenever we have a device and if one is present already don't bother claiming extra resources for hotplug.
- for (cap = pci_config_readb(pci->bdf, PCI_CAPABILITY_LIST); cap;
cap = pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_NEXT))if (pci_config_readb(pci->bdf, cap + PCI_CAP_LIST_ID) == cap_id)return cap;I would also limit this to 256 iterations, to make sure we dont' get into an infinite loop with a broken device.
Good point.
Yes, thanks! sending v2. Marcel
cheers, Gerd