drm/i915: Refactor common code to load initial power context

We load a context (the kernel context) on both module load and resume in
order to initialise some logical state onto the GPU. We can use the same
routine for both operations, which will become more useful as we
refactor rc6/rps enabling.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190308093657.8640-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -2877,6 +2877,22 @@ static bool switch_to_kernel_context_sync(struct drm_i915_private *i915)
 	return result;
 }
 
+static bool load_power_context(struct drm_i915_private *i915)
+{
+	if (!switch_to_kernel_context_sync(i915))
+		return false;
+
+	/*
+	 * 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);
+
+	return true;
+}
+
 static void
 i915_gem_idle_work_handler(struct work_struct *work)
 {
@@ -4451,7 +4467,7 @@ void i915_gem_resume(struct drm_i915_private *i915)
 	intel_uc_resume(i915);
 
 	/* Always reload a context for powersaving. */
-	if (i915_gem_switch_to_kernel_context(i915))
+	if (!load_power_context(i915))
 		goto err_wedged;
 
 out_unlock:
@@ -4616,7 +4632,7 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 	struct i915_gem_context *ctx;
 	struct intel_engine_cs *engine;
 	enum intel_engine_id id;
-	int err;
+	int err = 0;
 
 	/*
 	 * As we reset the gpu during very early sanitisation, the current
@@ -4649,19 +4665,12 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 			goto err_active;
 	}
 
-	if (!switch_to_kernel_context_sync(i915)) {
-		err = -EIO; /* Caller will declare us wedged */
+	/* Flush the default context image to memory, and enable powersaving. */
+	if (!load_power_context(i915)) {
+		err = -EIO;
 		goto err_active;
 	}
 
-	/*
-	 * 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;
@@ -4727,19 +4736,10 @@ static int __intel_engines_record_defaults(struct drm_i915_private *i915)
 err_active:
 	/*
 	 * If we have to abandon now, we expect the engines to be idle
-	 * and ready to be torn-down. First try to flush any remaining
-	 * request, ensure we are pointing at the kernel context and
-	 * then remove it.
+	 * and ready to be torn-down. The quickest way we can accomplish
+	 * this is by declaring ourselves wedged.
 	 */
-	if (WARN_ON(i915_gem_switch_to_kernel_context(i915)))
-		goto out_ctx;
-
-	if (WARN_ON(i915_gem_wait_for_idle(i915,
-					   I915_WAIT_LOCKED,
-					   MAX_SCHEDULE_TIMEOUT)))
-		goto out_ctx;
-
-	i915_gem_contexts_lost(i915);
+	i915_gem_set_wedged(i915);
 	goto out_ctx;
 }