On Wed, Apr 06, 2022 at 09:51:24AM +0200, Christian König wrote:
> Even for explicit synchronization we should wait for kernel fences.
Yeah I don't think this patch makes much sense, because aside from etnaviv
there's also msm and lima which allow you to ignore all dma_resv fences
completely.
But it's also not an issue because these drivers don't move buffers, don't
have any other kernel fences and also don't do dynamic importing. I think
the real fix is replacing the write argument to
drm_sched_job_add_implicit_dependencies with dma_resv_usage and rolling
that out.
I'd just drop this for now, seems like a detour.
-Daniel
>
> Signed-off-by: Christian König <christian.koenig@xxxxxxx>
> ---
> drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c | 27 ++++++++++++++++++--
> 1 file changed, 25 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
> index 98bb5c9239de..3fedd29732d5 100644
> --- a/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
> +++ b/drivers/gpu/drm/etnaviv/etnaviv_gem_submit.c
> @@ -171,6 +171,26 @@ static int submit_lock_objects(struct etnaviv_gem_submit *submit,
> return ret;
> }
>
> +/* TODO: This should be moved into the GPU scheduler if others need it */
> +static int submit_fence_kernel_sync(struct etnaviv_gem_submit *submit,
> + struct dma_resv *resv)
> +{
> + struct dma_resv_iter cursor;
> + struct dma_fence *fence;
> + int ret;
> +
> + dma_resv_for_each_fence(&cursor, resv, DMA_RESV_USAGE_KERNEL, fence) {
> + /* Make sure to grab an additional ref on the added fence */
> + dma_fence_get(fence);
> + ret = drm_sched_job_add_dependency(&submit->sched_job, fence);
> + if (ret) {
> + dma_fence_put(fence);
> + return ret;
> + }
> + }
> + return 0;
> +}
> +
> static int submit_fence_sync(struct etnaviv_gem_submit *submit)
> {
> int i, ret = 0;
> @@ -183,8 +203,11 @@ static int submit_fence_sync(struct etnaviv_gem_submit *submit)
> if (ret)
> return ret;
>
> - if (submit->flags & ETNA_SUBMIT_NO_IMPLICIT)
> - continue;
> + if (submit->flags & ETNA_SUBMIT_NO_IMPLICIT) {
> + ret = submit_fence_kernel_sync(submit, robj);
> + if (ret)
> + return ret;
> + }
>
> ret = drm_sched_job_add_implicit_dependencies(&submit->sched_job,
> &bo->obj->base,
> --
> 2.25.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
