I have found the line of code that causes the BAR values to change from what
the bootloader/bios set them to, and makes them zero. It is in pciide.c, in
the pdc202xx_chip_map(sc, pa) routine, it is the line:
  pci_conf_write(sc->sc_pc, sc->sc_tag, PDC2xx_STATE, st);

The value of PDC2xx_STATE is 0x50

Do you know why this would cause the BAR at offset 0x18 to be changed from a
non-zero value to zero? This is what is causing the card not to work.

Thanks
 Bruce