This patch adds a new "I/O watchdog" role to the existing
timer code, and cleans it up a bit.  If you want to run
EHCI without IRQs, it's now simple:  disable them, and
tweak the timer appropriately.

The patch should help with these reported problems.

    (a) Bulk I/O sometimes seems to stop progressing.  Not
        trouble in itself, but usb-storage and scsi could
        wedge deeply because of bugs in their fault recovery;
        and then the problems could break khubd and rmmod...

    (b) Some periodic transfers need to be "jumpstarted".
        Usually seen with a high speed hub.