Hi Laurent # add Niklas Sorry for my suport late response. Thanks Niklas for reminder > (With a question for Morimoto-san below) (snip) > > >> + } while (++i < NR_READS_TO_WAIT); > > > > > > How long does the DMA engine typically need to stop ? Is there a safe > > > upper bound ? > > > > I have tested it many times. The highest number of retries was 3 which > > occurred not very frequently. Normally it is 1-2 > > Morimoto-san, could you check with the hardware team if there's a worst case > guarantee regarding how long the channel could take to stop ? You need to wait maximum 0.7ms for it. both for Gen2/Gen3. In worst case, it needs 8 request times. If 1 request is 20,000 cycle 20,000cycle x 8request x [4ns/cylce] = 640,000ns > 700us -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
