RADEON_CLOCK_CNTL_INDEX
bus_write_1(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX, (reg & 0x3f));
save = bus_read_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX);
bus_write_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX, tmp);
bus_write_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX, save);
bus_write_1(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX,
save = bus_read_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX);
bus_write_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX, tmp);
bus_write_4(sc->sc_memr, RADEON_CLOCK_CNTL_INDEX, save);