Re: [PATCH v3 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg*

[Christoph Hellwig]

On Thu, Nov 29, 2018 at 09:42:50AM -0500, Rob Clark wrote:
> Maybe the thing we need to do is just implement a blacklist of
> compatible strings for devices which should skip the automatic
> iommu/dma hookup.  Maybe a bit ugly, but it would also solve a problem
> preventing us from enabling per-process pagetables for a5xx (where we
> need to control the domain/context-bank that is allocated by the dma
> api).

You can detach from the dma map attachment using arm_iommu_detach_device,
which a few drm drivers do, but I don't think this is the problem.