[PATCH] SB600 for the Nemo board has non-zero devices on non-root bus

[Christian Zigotzky]

On 30.11.2017 23:42, Bjorn Helgaas wrote:
 >
 > 00:11.0 claims to be a PCIe Root Port leading to [bus 05-06]. That
 > means there's a Link (presumably this A-Link II Express thing), and the
 > downstream end of the Link *should* be a PCIe Upstream Port on bus 05,
 > but no such device is visible.  I suppose the SB600 does implement
 > some sort of PCIe Port there, but keeps it invisible to software, and
 > at the same time, contains an invisible bridge that connects the Link
 > to all the conventional PCI devices on bus 05.
 >
 > When we scan bus 05, we do this:
 >
 >   pci_scan_child_bus_extend(bus=05)
 >     for (devfn = 0; devfn < 0x100; devfn += 8)
 >       pci_scan_slot(05, 00.0)
 >         pci_scan_single_device
 >           pci_scan_device(05, 00.0)           # fails; no 05:00.0
 >       pci_scan_slot(05, 01.0)
 >         only_one_child(bus=05)
 >           parent = 00:11.0
 >           pci_pcie_type(00:11.0) == ROOT_PORT # returns true
 >
 > Since only_one_child() sees that 00:11.0 is a Root Port, we give up
 > before we even get to the PCI_SCAN_ALL_PCIE_DEVS test.
 >
 > I *think* something like the patch below should make this work if you
 > use the "pci=pcie_scan_all" parameter.  We have some x86 DMI quirks
 > that set PCI_SCAN_ALL_PCIE_DEVS automatically.  I don't know how to do
 > something similar on powerpc, but maybe you do?
 >

Hi Bjorn,

I tested your new patch today. It boots with the boot argument 
"pci=pcie_scan_all". Well done! :-)

It doesn't boot without the boot argument "pci=pcie_scan_all".

Many thanks for your help.

Cheers,
Christian

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