This patch makes the usbcore PCI suspend/resume logic behave
much better.  In particular:

  - Even HCs without PCI PM support will normally be able
    to support global suspend, saving power ... and will
    need to resume later.  Let them try to suspend; lots
    of not-that-old USB controllers don't have PM caps.

  - Saner order for the boilerplate PCI stuff.  It also
    explicitly disables the IRQ and DMA, which aren't
    available in D1/D2/D3 states anyway.

  - Uses pci_enable_wake() when the root hub supports
    remote wakeup.  Didn't fully work in one test setup;
    that controller's PME# was evidently ignored.  (Not
    enabled unless CONFIG_USB_SUSPEND.)

It worked for me with brief tests with the current 2.6.6-rc
uhci-hcd with one old UHCI; more extensive ones with various
OHCIs (using patches which I'll post soonish); and not at all
with EHCI (where PM hasn't ever worked).

Those of you who've been having PM problems might find
this helpful as-is, though I think that unless you're
using UHCI you'll also need an HCD patch.

- Dave