VIGRA_REG_VRAM
if (sbus_bus_map(bt, sa->sa_reg[VIGRA_REG_VRAM].sbr_slot,
sa->sa_reg[VIGRA_REG_VRAM].sbr_offset,
sc->sc_paddr = sbus_bus_addr(bt, sa->sa_reg[VIGRA_REG_VRAM].sbr_slot,
sa->sa_reg[VIGRA_REG_VRAM].sbr_offset);