Random issues with xhci

[Sean Bruno]

xhci0 at pci0:2:0:0:	class=0x0c0330 card=0x84881043 chip=0x10421b21
rev=0x00 hdr=0x00
    vendor     = 'ASMedia Technology Inc.'
    device     = 'ASM1042 SuperSpeed USB Host Controller'
    class      = serial bus
    subclass   = USB


I can't quite ping down a specific test case with this usb controller.
I see that, sometimes, connecting devices to it or rebooting with
devices connected to it will fail with a constant device timeout
message.

Any ideas on some better test cases with various bits of USB gear?  

sean