[alsa-devel] What can change after suspend ?

I'm adding suspend/resume support to echoaudio drivers. I was reading /Documentation/power/pci.txt:

" pci_set_power_state(PCI_D0); pci_restore_state(); /* device's irq possibly is changed, driver should take care */ "

The card does not support D[0-3] states. The driver suspends the card by turning the DSP off, without changing the PCI state. Can IRQ, memory mapped regions, whatever, change on resume ? Are pci_save_state() and pci_enable_wake() useful/required in this case ?