[virtio-dev] [PATCH 2/2] drm/virtio: add iommu support.

[Gerd Hoffmann]

  Hi,

> buffer.  I tried to put a dma_sync_sg_for_device() on virtio_gpu_object obj->pages-sgl
> before VIRTIO_GPU_CMD_TRANSFER_TO_HOST_2D is sent.  This fixes the kernel console path.

That should be the right place.

> Once display manger is kicked off for example (sudo systemctl start lightdm.service) and
> resource id 3 gets created from user space down, it still gives a blank black screen.

Hmm.  I'd suspect there is simply a code path missing.  Can you send the
patch you have?

cheers,
  Gerd