On Mon, Oct 22, 2012 at 9:44 AM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: >> That (walking all parent nodes) is probably the safest thing to do. I'm >> not sure whether it's optimal. It would likely depend on whether you >> can meaningfully have a bridge that's faster on the downstream side than >> on the upstream. > > This is architecture goo at heart - would this be better as a helper in > the PCI and arch PCI code ? Good point. POWER is not the only architecture where host bridges do not appear as devices in PCI config space -- ia64 has that, too. So the comment is too specific. The link is a point-to-point thing, so this should be a local negotiation between the radeon device and the upstream bridge. I don't see the point of walking any farther up the chain. drm_pcie_get_speed_cap_mask() should also be changed to use pcie_capability_read_dword() to avoid any issues with v1/v2 PCI Express Capability structures. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
