CFREG_REV
id = (bus_space_read_1(h.memt, h.memh, ptr + CFREG_REV) &
cfxga_write_2(sc, CFREG_REV, 0x80 | (CM_REGSEL << 8));
cfxga_write_2(sc, CFREG_REV, 0 | (CM_MEMSEL << 8));