On Wed, Mar 06, 2019 at 09:29:36AM +0100, Uwe Kleine-König wrote:
> On Mon, Mar 04, 2019 at 11:02:36PM +0000, Trent Piepho wrote:
> > Add the boolean module parameter "use_dma" to control the use of DMA by
> > the driver. There are about two dozen other drivers with a "use_dma"
> > parameter of some sort.
> Wouldn't it be more sensible to change the driver to only use DMA for
> big transfers? That would look much more reasonable than a global
> parameter that affects all transfers on all spi interfaces. The spi-mxs
> driver does something like that. (In mxs_spi_transfer_one look for "if
> (t->len < 32) {".)
Yes, this is the standard solution and it ensures that things work well
for people if they just use the driver without knowing the magic
incanation, and it also avoids issues for devices which do a combination
of both large and small transfers.
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