Messages in this thread | | | Date | Wed, 11 Dec 2019 09:15:41 +0100 | From | Gerd Hoffmann <> | Subject | Re: [PATCH] drm/virtio: fix mmap page attributes |
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Hi,
> There's similar code in udl, [1] which still uses writecombine for > imported buffers. Virtio does not need this?
virtio doesn't support dma-buf imports (yet). So no worries for now.
Why pick writecombine for the imported buffer btw? It'll probably be correct for the majority of imports, but it still looks like a educated guess to me. What if you import from vgem?
I guess we should either ... (1) Ask the exporting driver to handle things, simliar to how it is done for vmaps already, probably by calling dma_buf_mmap(), or (2) Refuse to mmap imported objects via drm api.
> Aside from this, do you think we could handle all special cases within > shmem?
Probably makes sense to teach shmem helpers about caching.
cheers, Gerd
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