Re: [PATCH v4 3/4] drm/virtio: add in/out fence support for explicit synchronization

[Emil Velikov]

On Mon, 5 Nov 2018 at 11:42, Robert Foss <robert.foss@xxxxxxxxxxxxx> wrote:
>
> When the execbuf call receives an in-fence it will get the dma_fence
> related to that fence fd and wait on it before submitting the draw call.
>
> On the out-fence side we get fence returned by the submitted draw call
> and attach it to a sync_file and send the sync_file fd to userspace. On
> error -1 is returned to userspace.
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxx>
> Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxxxxx>
> Suggested-by: Rob Herring <robh@xxxxxxxxxx>
> Reviewed-by: Emil Velikov <emil.velikov@xxxxxxxxxxxxx>
> ---
>
> Changes since v3:
>  - Move all in_fence handling to the same VIRTGPU_EXECBUF_FENCE_FD_IN block
Fwiw my suggestion was to explicitly document whether the IOCTL can
support, simultaneously, IN and OUT fence.
Merging the two patches makes things a bit meh. But as before - it's
for Gerd to make the final call.

-Emil