On Tue, Jan 27, 2015 at 09:31:26AM +0100, Thomas Hellstrom wrote: > On 01/27/2015 09:15 AM, Thierry Reding wrote: > > Are you referring to the 4 GiB - 1 comment? The point I was trying to > > make is not that the granularity of the IOVA space needs to be 1 byte > > but rather that using an unsigned long for a size on a 32-bit machine > > will give you 4 GiB - 1 addresses. The IOMMU page size is still 4 KiB > > for Tegra. > > I was rather referring to that if the range manager (drm_mm) is set up > to manage pages instead of bytes > (like, for example, the TTM VM address space), you'd get 4G - 1 pages, > which, I believe, is sufficient on most 32 bit systems? It'd probably also be more efficient on 32-bit systems rather than shifting them over to using 64-bit quantities. If the allocation granularity were to move to pages, would it be worth moving to a pfn-based addressing system too, rather than sticking with a byte address there too? -- FTTC broadband for 0.8mile line: currently at 10.5Mbps down 400kbps up according to speedtest.net. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
