drm/i915/debugfs: Do not report currently active engine when describing objects

It is not very useful to have code which tries to report a rapidly
transient state which will not report anything majority of the time,
especially since it is currently only used from
<debugfs>/i915_gem_framebuffers.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210915114153.951670-1-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/gem/i915_gem_object.h

@@ -503,23 +503,6 @@ i915_gem_object_finish_access(struct drm_i915_gem_object *obj)
 	i915_gem_object_unpin_pages(obj);
 }
 
-static inline struct intel_engine_cs *
-i915_gem_object_last_write_engine(struct drm_i915_gem_object *obj)
-{
-	struct intel_engine_cs *engine = NULL;
-	struct dma_fence *fence;
-
-	rcu_read_lock();
-	fence = dma_resv_get_excl_unlocked(obj->base.resv);
-	rcu_read_unlock();
-
-	if (fence && dma_fence_is_i915(fence) && !dma_fence_is_signaled(fence))
-		engine = to_request(fence)->engine;
-	dma_fence_put(fence);
-
-	return engine;
-}
-
 void i915_gem_object_set_cache_coherency(struct drm_i915_gem_object *obj,
 					 unsigned int cache_level);
 void i915_gem_object_flush_if_display(struct drm_i915_gem_object *obj);

drivers/gpu/drm/i915/i915_debugfs.c

@@ -140,7 +140,6 @@ void
 i915_debugfs_describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 {
 	struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
-	struct intel_engine_cs *engine;
 	struct i915_vma *vma;
 	int pin_count = 0;
 
@@ -230,10 +229,6 @@ i915_debugfs_describe_obj(struct seq_file *m, struct drm_i915_gem_object *obj)
 		seq_printf(m, " (stolen: %08llx)", obj->stolen->start);
 	if (i915_gem_object_is_framebuffer(obj))
 		seq_printf(m, " (fb)");
-
-	engine = i915_gem_object_last_write_engine(obj);
-	if (engine)
-		seq_printf(m, " (%s)", engine->name);
 }
 
 static int i915_gem_object_info(struct seq_file *m, void *data)