On 11/04/2013 05:27 PM, Daniel Vetter wrote: > On Mon, Nov 04, 2013 at 05:57:39AM -0800, Thomas Hellstrom wrote: >> The code handles three different cases: >> 1) physical page addresses. The ttm page array is used. >> 2) DMA subsystem addresses. A scatter-gather list is used. >> 3) Coherent pages. The ttm dma pool is used, together with the dma_ttm >> array os dma_addr_t >> >> Signed-off-by: Thomas Hellstrom <thellstrom@xxxxxxxxxx> >> Reviewed-by: Jakob Bornecrantz <jakob@xxxxxxxxxx> > For i915.ko use we've added page iterators which should walk the physical > backing storage. > > commit a321e91b6d73ed011ffceed384c40d2785cf723b > Author: Imre Deak <imre.deak@xxxxxxxxx> > Date: Wed Feb 27 17:02:56 2013 -0800 > > lib/scatterlist: add simple page iterator > > Yes, I saw those iterators, (nice stuff!) and my patch are using them as a "base class", handling also TTM page - and dma address arrays basically with the same interface. In the long run we might want to move ttm over to sg_tables as well. One problem, though, the page iterators break in the mapped case where sg_dma_len(sg) != sg_len(sg). An iommu implementation is allowed to reduce the sg list to a single segment, in which case those page iterators will fall apart. I was planning to see if I could fix that up, but unfortunately there is no generic dma_to_phys. It all works now because intel_iommu, amd_iommu and swiotlb all keep the number of entries in an sg list across mapping.... /Thomas ------------------------------------------------------------------------------ Android is increasing in popularity, but the open development platform that developers love is also attractive to malware creators. Download this white paper to learn more about secure code signing practices that can help keep Android apps secure. http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk -- _______________________________________________ Dri-devel mailing list Dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
