On Mon, Aug 24, 2020 at 11:52 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > > On Sat, Aug 22, 2020 at 10:52:54AM -0700, Rob Clark wrote: > > From: Rob Clark <robdclark@xxxxxxxxxxxx> > > > > Now that it isn't causing problems to use dma_map/unmap, we can drop the > > hack of using dma_sync in certain cases. > > Great to see! What did solve the problems? should be 0e764a01015dfebff8a8ffd297d74663772e248a ("iommu/arm-smmu: Allow client devices to select direct mapping") I still need to confirm whether qcom_iommu needs a similar thing, but I think it is ok as the iommu phandle link is down one level on the 'mdp' device, rather than attached to the toplevel drm device. BR, -R