Power saving mode

I have a card which can enter a low power state. It turns off some components but it leaves the PCI bus interface active. To bring the card back to life it has to be reinitialized from scratch. What "D" state is it ? PCI power management papers say that already in D1 state i/o space is disabled. I'm a bit confused... I can't find any doc about D0.5 :)

Bye.