Mark Lord <liml@xxxxxx> wrote: > Sebastian Kuzminsky wrote: > > Hi folks, hdparm's got me confused. > .. > > "hdparm /dev/hda" says: > . > > DMA: mdma0 mdma1 *mdma2 > > Cycle time: min=120ns recommended=120ns > > PIO: pio0 pio1 pio2 pio3 pio4 > > Cycle time: no flow control=120ns IORDY flow control=120ns > .. > > The *mdma2 means, that if you were to issue a READ_DMA (or WRITE_DMA) > command to the drive, the drive is expecting the host to use > the multiword-dma-2 protocol and timings for it. > > Meanwhile, the host may, at its option, simply use PIO commands (READ, WRITE) > instead of DMA, any time it chooses. > > Drives have both a DMA mode, and a PIO mode, each of which is selected > and used independently of the other. Ok thanks! So how do I know what PIO mode the drive wants to use? And how do I tell the HBA what PIO mode to use? -- Sebastian Kuzminsky - : 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
