On Fri, May 29, 2020 at 4:59 AM Simon Ser <contact@xxxxxxxxxxx> wrote: > > On Thursday, May 28, 2020 5:49 PM, Marek Olšák <maraeo@xxxxxxxxx> wrote: > > > On most hardware, there is a minimum pitch alignment for linear and > > any greater multiple of the alignment is fine. > > > > On Navi, the pitch in bytes for linear must be > > align(width * bpp / 8, 256). That's because the hw computes the pitch > > from the width and doesn't allow setting a custom pitch. For that > > reason, multi-GPU sharing might not be possible if the other GPU > > doesn't align the pitch in exactly the same way. > > OK. In this case I think it's fine to make the DMA-BUF import fail, as > we've suggested on IRC. The more-or-less planned fix for these buffer > sharing issues is to revive the buffer constraints proposal from the > allocator project. It's a lot of work though. I get that, but why explicitly limit modifiers then? Shouldn't we try and do the best we can with what we have now? If not the situation is not much better than what we have now. Why go through the effort or adding modifer support in the first place if they are mostly useless? I don't quite get what we are trying to do with them. What does this mean "Modifiers must uniquely encode buffer layout"? We have a number of buffer layouts that are the same from a functional standpoint, but they have different alignment requirements depending on the chip and the number of memory channels, etc. Would those be considered the same modifer? If not, then we are sort of implicitly encoding alignment requirements into the modifier. Alex _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
