On Wed, Jun 28, 2023 at 8:58 AM Gurchetan Singh
<gurchetansingh@xxxxxxxxxxxx> wrote:
>
> We don't want to create a fence for every command submission. It's
> only necessary when userspace provides a waitable token for submission.
> This could be:
>
> 1) bo_handles, to be used with VIRTGPU_WAIT
> 2) out_fence_fd, to be used with dma_fence apis
> 3) a ring_idx provided with VIRTGPU_CONTEXT_PARAM_POLL_RINGS_MASK
> + DRM event API
> 4) syncobjs in the future
>
> The use case for just submitting a command to the host, and expected
> no response. For example, gfxstream has GFXSTREAM_CONTEXT_PING that
> just wakes up the host side worker threads. There's also
> CROSS_DOMAIN_CMD_SEND which just sends data to the Wayland server.
>
> This prevents the need to signal the automatically created
> virtio_gpu_fence.
>
> Signed-off-by: Gurchetan Singh <gurchetansingh@xxxxxxxxxxxx>
> Reviewed-by: <dmitry.osipenko@xxxxxxxxxxxxx>
> ---
> v2: Fix indent (Dmitry)
>
> drivers/gpu/drm/virtio/virtgpu_submit.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/virtio/virtgpu_submit.c b/drivers/gpu/drm/virtio/virtgpu_submit.c
> index cf3c04b16a7a..8c7e15c31164 100644
> --- a/drivers/gpu/drm/virtio/virtgpu_submit.c
> +++ b/drivers/gpu/drm/virtio/virtgpu_submit.c
> @@ -168,9 +168,13 @@ static int virtio_gpu_init_submit(struct virtio_gpu_submit *submit,
>
> memset(submit, 0, sizeof(*submit));
>
> - out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
> - if (!out_fence)
> - return -ENOMEM;
> + if ((exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_OUT) ||
> + ((exbuf->flags & VIRTGPU_EXECBUF_RING_IDX) &&
> + (vfpriv->ring_idx_mask & BIT_ULL(ring_idx))) ||
> + exbuf->num_bo_handles)
> + out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
> + else
> + out_fence = NULL;
>
> err = virtio_gpu_fence_event_create(dev, file, out_fence, ring_idx);
> if (err) {
> --
Ping for additional reviews or merge.
> 2.41.0.162.gfafddb0af9-goog
>
