On Wed, 3 Mar 2010 15:25:52 +0800 David Brownell <david-b@xxxxxxxxxxx> wrote: > If someone decided to update a SPI controller driver to avoid DMA in > some cases, in favor of PIO, they could already code such heuristics > without needing your proposed hinting from upper layers. > > The result in the low-level driver would be just to use a different > test (maybe "is this a one-word transfer?" instead of checking your > per-transfer "use PIO?" hint) Yup, good point, controller driver can be smarter Thanks, Feng > before kicking in whatever logic you > think would improve performance (by eliminating DMA setup and teardown > costs, including cache cleaning). > > - Dave > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
