1 Interrupt acknowledgement loop
The logic in the windows driver is not clear. The interrupt pipe in configured to send interrupts only in case the INTA# pin changes state. This means we get two urbs, one when the pin is raised, then another one that's sent once the pin goes back to zero (once we have acknowledged the interrupts in the device).
After firmware upload, we need to wait for this vector from the prism interrupt's register :
80004004
the highest bit seems to be set almost every time we read it. I don't know if we must acknowledge it or not. Other bits i don't know their meaning... though they seem to be the important ones. They're not listed in the original isl pci driver.