Alan Cox <alan <at> lxorguk.ukuu.org.uk> writes: > > SFF 8038i covers the standard taskfile IDE class PCI device interface for > PIO and DMA. It also covers the alternate ADMA interface. > >> Since DMA controller details may vary according to hardware, I >> would have expected that ata_fill_sg() would be one of the overloadable >> function entries with a driver-specific function that knew about >> the DMA controller niceties, and how to stuff a sg entry. > > It is not directly however but by overloading qc_prep. That makes more > sense than overloading fill_sg as not all controllers fit a simple > SFF like scatter/gather list model in the first place. > > Alan > - I note also that Intel's Serial ATA AHCI spec has a 22-bit DMA byte count in the PRDT, so 0 == 64k cannot be assumed here either. Cheers, MikeW - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
