Today, just for fun, I picked up a PCI USB controller card today at
the local giant computer store, a "SIIG USB Dualport PCI". I dropped
it into my alphastation 200 and built a kernel (from yesterday's
sources) with USB code in it. Upon rebooting, it looked okay at probe
time:

ohci0 at pci0 dev 12 function 0: Opti RM861HA (rev. 0x10)
ohci0: interrupting at isa irq 10
ohci0: OHCI version 1.0, legacy support
usb0 at ohci0: USB revision 1.0
uhub0 at usb0
uhub0: Opti OHCI root hub, class 9/0, rev 1.00/1.00, addr 1
uhub0: 2 ports with 2 removable, self powered

(nothing else is using isa irq 10)

Once autoconfig got as far as enabling interrupts, all hell breaks
loose in the form of an unending stream of:

ohci0: scheduling overrun

messages on the console.

Where should I start looking? I may get to plug this into my other PCI
Alpha box (a pc164) a bit later, to see if it's local to the system; I
don't have any other systems with PCI to test the card on. Should I
suspect a damaged card? broken ohci code? broken interrupt controller
code? I'm not sure of a good way to check if the interrupt is actually
being asserted repeatedly or if the code is somehow failing to clear
it. 

        - Nathan