On 20/11/2019 12:28, Oliver O'Halloran wrote:
> Currently when using the normal (i.e not building pci_dev's from the DT
> node) probe method we only scan the devfn corresponding to the first child
> of the bridge's DT node. This doesn't make much sense to me, but it seems
> to have worked so far. At a guess it seems to work because in a PCIe
> environment the first downstream child will be at devfn 00.0.
>
> In any case it's completely broken when no pci_dn is available. Remove
> the PCI_DN checking and scan each of the device number that might be on
> the downstream bus.
Then why not just use pci_scan_child_bus()? Thanks,
> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> Signed-off-by: Oliver O'Halloran <ooh...@gmail.com>
> ---
> I'm not sure we should be using pci_scan_slot() directly here. Maybe
> there's some insane legacy reason for it.
> ---
> arch/powerpc/kernel/pci-hotplug.c | 15 ++++-----------
> 1 file changed, 4 insertions(+), 11 deletions(-)
>
> diff --git a/arch/powerpc/kernel/pci-hotplug.c
> b/arch/powerpc/kernel/pci-hotplug.c
> index d6a67f814983..85299c769768 100644
> --- a/arch/powerpc/kernel/pci-hotplug.c
> +++ b/arch/powerpc/kernel/pci-hotplug.c
> @@ -123,17 +123,10 @@ void pci_hp_add_devices(struct pci_bus *bus)
> if (mode == PCI_PROBE_DEVTREE) {
> /* use ofdt-based probe */
> of_rescan_bus(dn, bus);
> - } else if (mode == PCI_PROBE_NORMAL &&
> - dn->child && PCI_DN(dn->child)) {
> - /*
> - * Use legacy probe. In the partial hotplug case, we
> - * probably have grandchildren devices unplugged. So
> - * we don't check the return value from pci_scan_slot() in
> - * order for fully rescan all the way down to pick them up.
> - * They can have been removed during partial hotplug.
> - */
> - slotno = PCI_SLOT(PCI_DN(dn->child)->devfn);
> - pci_scan_slot(bus, PCI_DEVFN(slotno, 0));
> + } else if (mode == PCI_PROBE_NORMAL) {
> + for (slotno = 0; slotno < 255; slotno += 8)
> + pci_scan_slot(bus, slotno);
> +
> max = bus->busn_res.start;
> /*
> * Scan bridges that are already configured. We don't touch
>
--
Alexey
