> I looked at others open-source drivers, but I didn't find any hint.

drivers/ide/pci/pdc202xx_new.c in linux 2.6 has some extra init logic for
CONFIG_PPC_PMAC, which (interestingly) has special cases for
PCI_DEVICE_ID_PROMISE_2027[01]. hmm. the driver style is so different
that it's not entirely obvious whether netbsd does the same init...