On Fri, Apr 26, 2019 at 04:21:37PM +0200, Daniel Vetter wrote:
> On Fri, Apr 26, 2019 at 7:33 AM Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
> >
> > This reverts commit f4c34b1e2a37d5676180901fa6ff188bcb6371f8.
> >
> > Simliar to commit a0cecc23cfcb Revert "drm/virtio: drop prime
> > import/export callbacks". We have to do the same with qxl,
> > for the same reasons (it breaks DRI3).
> >
> > Drop the WARN_ON_ONCE().
> >
> > Fixes: f4c34b1e2a37d5676180901fa6ff188bcb6371f8
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
>
> Maybe we need some helpers for virtual drivers which only allow
> self-reimport and nothing else at all?
The current gem prime helpers handle this reasonable well,
I don't see a need for that.
More useful would be some way to signal this self-reimport capability
to userspace somehow. See DRM_PRIME_CAP_LOCAL patch.
Right now I have the choice to set DRM_PRIME_CAP_{IMPORT,EXPORT}, in
which case some userspace assumes it can do cross-driver export/import
and trips over that not working. Or I do not set
DRM_PRIME_CAP_{IMPORT,EXPORT}, which breaks DRI3 ...
> I think there's qxl, virgl,
export is implemented for virgl, and import should be possible too.
qxl/bochs is simliar to vmgfx, it could be done but dma-bufs would
basically be bounce buffers (need copy from/to vram) so probably not
worth the effort.
cheers,
Gerd
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