drm/amdgpu: Add warning message for INT SW fallback.

Signed-off-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -274,6 +274,7 @@ static void amdgpu_fence_fallback(struct timer_list *t)
 	struct amdgpu_ring *ring = from_timer(ring, t,
 					      fence_drv.fallback_timer);
 
+	DRM_INFO("Fallback to SW interrupt on ring %s due to HW interrupt time out", ring->name);
 	amdgpu_fence_process(ring);
 }