On Wed, Oct 26, 2016 at 8:12 AM, Dave Airlie <airlied@xxxxxxxxx> wrote: >>> Is anything on a driver to be able to tell when this is actually needed ? >>> How will driver developers know? Can you add a bit of documentation to >>> the API? If its transitive towards a secondary solution indicating so >>> would help driver developers. >> >> I'll plug the io-mapping stuff again here, and more specifically the >> userspace pte wrangling stuff we've added in 4.9 to i915_mm.c. Should >> probably move that one to the core. That way io_mapping takes care of the >> full reservartion, and allows you to on-demand kmap (for kernel) and write >> ptes. All nicely fast and all, and for bonus, also nicely encapsulated. > > Yeah I think ideally we'd want to move towards that, however we don't tend > to want to ioremap the full range even on 64-bit, which is what io-mapping does. Hm, I thought on 64 we have linear mappings of all the io space anyway, and they're essentially for free. Am I wrong and there's some overhead here too? -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
