On 08-05-19, 10:24, Jon Hunter wrote: > > On 05/05/2019 19:12, Dmitry Osipenko wrote: > > The DMA_PREP_INTERRUPT flag means that descriptor's callback should be > > invoked upon transfer completion and that's it. For some reason driver > > completely disables the hardware interrupt handling, leaving channel in > > unusable state if transfer is issued with the flag being unset. Note > > that there are no occurrences in the relevant drivers that do not set > > the flag, hence this patch doesn't fix any actual bug and merely fixes > > potential problem. > > > > Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx> > > >From having a look at this, I am guessing that we have never really > tested the case where DMA_PREP_INTERRUPT flag is not set because as you > mentioned it does not look like this will work at all! That is a fair argument > > Is there are use-case you are looking at where you don't set the > DMA_PREP_INTERRUPT flag? > > If not I am wondering if we should even bother supporting this and warn > if it is not set. AFAICT it does not appear to be mandatory, but maybe > Vinod can comment more on this. This is supposed to be used in the cases where you submit a bunch of descriptors and selectively dont want an interrupt in few cases... Is this such a case? Thanks ~Vinod
