pciide_dma_start
sc->sc_wdcdev.dma_start = pciide_dma_start;
extern void pciide_dma_start(void *, int, int);
sc->sc_wdcdev.dma_start = pciide_dma_start;
sc->sc_wdcdev.dma_start = pciide_dma_start;
void pciide_dma_start(void*, int, int);
pciide_dma_start(v, channel, drive);
sc->sc_wdcdev.dma_start = pciide_dma_start;
sc->sc_wdcdev.dma_start = pciide_dma_start;
sc->sc_wdcdev.dma_start = pciide_dma_start;