IDEIC_RINDEX
val = pci_config_get8(isa_handle, IDEIC_RINDEX);
pci_config_put8(isa_handle, IDEIC_RINDEX, val & 0xFB);
pci_config_put8(isa_handle, IDEIC_RINDEX, val);
pci_config_put8(isa_handle, IDEIC_RINDEX, val & 0xF7);
pci_config_put8(isa_handle, IDEIC_RINDEX, val);