On Tue, Jan 22, 2019 at 10:07:07PM +0100, Ard Biesheuvel wrote: > Yes, so much was clear. And the reason this breaks on some arm64 > systems is because > a) non-snooped PCIe TLP attributes may be ignored, and > b) non-x86 CPUs do not snoop the caches when accessing uncached mappings. > > I don't think there is actually any disagreement on this part. And I > think my patch is reasonable, only Christoph is objecting to it on the > grounds that drivers should not go around the DMA API and create > vmap()s of DMA pages with self chosen attributes. I object to it on various grounds. While the above is correct it really is a mid to long-term fix. But even in the short term your patch just maintains a random list of idefs in a random driver, pokes into the dma-mapping internals and lacks any comments in the code explaining on what is going on, leading to futher cargo culting. So it very clearly is not acceptable. _______________________________________________ amd-gfx mailing list amd-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/amd-gfx
