drm/amdgpu: always backup and reemit fences

If when we backup the ring contents for reemit before a
ring reset, we skip jobs associated with the bad
context, however, we need to make sure the fences
are reemited as unprocessed submissions may depend on
them.

v2: clean up fence handling, make helpers static

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 155a748)

Author: alexdeucher

drivers/gpu/drm/amd/amdgpu/amdgpu_fence.c

@@ -89,6 +89,16 @@ static u32 amdgpu_fence_read(struct amdgpu_ring *ring)
 	return seq;
 }
 
+static void amdgpu_fence_save_fence_wptr_start(struct amdgpu_fence *af)
+{
+	af->fence_wptr_start = af->ring->wptr;
+}
+
+static void amdgpu_fence_save_fence_wptr_end(struct amdgpu_fence *af)
+{
+	af->fence_wptr_end = af->ring->wptr;
+}
+
 /**
  * amdgpu_fence_emit - emit a fence on the requested ring
  *
@@ -116,8 +126,10 @@ int amdgpu_fence_emit(struct amdgpu_ring *ring, struct amdgpu_fence *af,
 		       &ring->fence_drv.lock,
 		       adev->fence_context + ring->idx, seq);
 
+	amdgpu_fence_save_fence_wptr_start(af);
 	amdgpu_ring_emit_fence(ring, ring->fence_drv.gpu_addr,
 			       seq, flags | AMDGPU_FENCE_FLAG_INT);
+	amdgpu_fence_save_fence_wptr_end(af);
 	amdgpu_fence_save_wptr(af);
 	pm_runtime_get_noresume(adev_to_drm(adev)->dev);
 	ptr = &ring->fence_drv.fences[seq & ring->fence_drv.num_fences_mask];
@@ -742,10 +754,6 @@ void amdgpu_fence_driver_guilty_force_completion(struct amdgpu_fence *af)
 		/* if we've already reemitted once then just cancel everything */
 		amdgpu_fence_driver_force_completion(af->ring);
 		af->ring->ring_backup_entries_to_copy = 0;
-	} else {
-		/* signal the guilty fence */
-		amdgpu_fence_write(ring, (u32)af->base.seqno);
-		amdgpu_fence_process(ring);
 	}
 }
 
@@ -795,9 +803,15 @@ void amdgpu_ring_backup_unprocessed_commands(struct amdgpu_ring *ring,
 			 * just save the content from other contexts.
 			 */
 			if (!fence->reemitted &&
-			    (!guilty_fence || (fence->context != guilty_fence->context)))
+			    (!guilty_fence || (fence->context != guilty_fence->context))) {
 				amdgpu_ring_backup_unprocessed_command(ring, wptr,
 								       fence->wptr);
+			} else if (!fence->reemitted) {
+				/* always save the fence */
+				amdgpu_ring_backup_unprocessed_command(ring,
+								       fence->fence_wptr_start,
+								       fence->fence_wptr_end);
+			}
 			wptr = fence->wptr;
 			fence->reemitted++;
 		}

drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h

@@ -144,12 +144,15 @@ struct amdgpu_fence {
 	struct amdgpu_ring		*ring;
 	ktime_t				start_timestamp;
 
-	/* wptr for the fence for resets */
+	/* wptr for the total submission for resets */
 	u64				wptr;
 	/* fence context for resets */
 	u64				context;
 	/* has this fence been reemitted */
 	unsigned int			reemitted;
+	/* wptr for the fence for the submission */
+	u64				fence_wptr_start;
+	u64				fence_wptr_end;
 };
 
 extern const struct drm_sched_backend_ops amdgpu_sched_ops;