drm/i915: Park the GPU on module load

Once we have flushed the first request through the system to both load a
context and record the default state; tell the GPU to park and idle
itself, putting itself immediately (hopefully at least) into a
powersaving state, and allowing ourselves to start from known state
after setting up all our bookkeeping.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180920161343.1117-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -5419,6 +5419,14 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 
 	assert_kernel_context_is_current(i915);
 
+	/*
+	 * Immediately park the GPU so that we enable powersaving and
+	 * treat it as idle. The next time we issue a request, we will
+	 * unpark and start using the engine->pinned_default_state, otherwise
+	 * it is in limbo and an early reset may fail.
+	 */
+	__i915_gem_park(i915);
+
 	for_each_engine(engine, i915, id) {
 		struct i915_vma *state;
 		void *vaddr;