CS4280_DCHUNK
error = cs4280_allocmem(sc, CS4280_DCHUNK, CS4280_DALIGN, p);
if (blksize >= CS4280_DCHUNK) {
sc->sc_pn = sc->sc_ps + CS4280_DCHUNK;
memcpy(sc->sc_pbuf, start, CS4280_DCHUNK);