[Intel-gfx] [PATCH 04/11] drm/panfrost: Fix implicit sync

[Daniel Vetter]

Currently this has no practial relevance I think because there's not
many who can pull off a setup with panfrost and another gpu in the
same system. But the rules are that if you're setting an exclusive
fence, indicating a gpu write access in the implicit fencing system,
then you need to wait for all fences, not just the previous exclusive
fence.

panfrost against itself has no problem, because it always sets the
exclusive fence (but that's probably something that will need to be
fixed for vulkan and/or multi-engine gpus, or you'll suffer badly).
Also no problem with that against display.

With the prep work done to switch over to the dependency helpers this
is now a oneliner.

Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
Cc: Rob Herring <robh at kernel.org>
Cc: Tomeu Vizoso <tomeu.vizoso at collabora.com>
Cc: Steven Price <steven.price at arm.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: "Christian König" <christian.koenig at amd.com>
Cc: linux-media at vger.kernel.org
Cc: linaro-mm-sig at lists.linaro.org
---
 drivers/gpu/drm/panfrost/panfrost_job.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 707d912ff64a..619d6104040c 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -203,9 +203,8 @@ static int panfrost_acquire_object_fences(struct drm_gem_object **bos,
 	int i, ret;
 
 	for (i = 0; i < bo_count; i++) {
-		struct dma_fence *fence = dma_resv_get_excl_rcu(bos[i]->resv);
-
-		ret = drm_gem_fence_array_add(deps, fence);
+		/* panfrost always uses write mode in its current uapi */
+		ret = drm_gem_fence_array_add_implicit(deps, bos[i], true);
 		if (ret)
 			return ret;
 	}
-- 
2.31.0