On Mon, 30 Jul 2018 03:11:59 +0000 Matthew Leon <matthewleon@xxxxxxxxx> wrote: > >> Hey Jisheng, > > >Hi, > > >> > > >In LKML, we'd better not top post. > > Noted. My apologies. > > >> Shouldn't we be splitting until all DMA blocks are less than 128M > boundary? > >> I am a noob, but I think we should be prepared for boundaries that when > >> split in two, will still be greater than 128M. Feel free to disagree but > >> please explain why I may be wrong. Thank-you. > > >the limitation is "DMA addr can't span 128MB boundary" rather than "must be > >less than 128MB", they are different. > > >And the max transfer size of one DMA desc is 64KB. > > >thanks > > I have misspoken. What if the DMA transfer size is 1024M? If we split in > two, then we have 2 transfers, each of which span 512M. So wouldn't we need > to split again to have 4 transfers, each of which span 128M? > the max transfer size of each desc is 64KB, how could it be 1024MB? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
