Re: [PATCH v2] drm/xen-front: Make shmem backed display buffer coherent

[Gerd Hoffmann]

  Hi,

> +	if (!dma_map_sg(dev->dev, xen_obj->sgt->sgl, xen_obj->sgt->nents,
> +			DMA_BIDIRECTIONAL)) {
> +		ret = -EFAULT;
> +		goto fail_free_sgt;
> +	}

Hmm, so it seems the arm guys could not come up with a suggestion how to
solve that one in a better way.  Ok, lets go with this then.

But didn't we agree that this deserves a comment exmplaining the purpose
of the dma_map_sg() call is to flush caches and that there is no actual
DMA happening here?

cheers,
  Gerd