drm/i915: unload: ensure that gem is idle

When the module unloads, all users should be gone, hence all bo references
held by userspace, too. This should already result in an idle ringbuffer.
Still, be paranoid and idle gem before starting the unload dance.

Also kill the call to i915_gem_lastclose under an if (kms), it's a noop
for kms.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/i915_dma.c

@@ -2249,11 +2249,18 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 int i915_driver_unload(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
 
 	spin_lock(&mchdev_lock);
 	i915_mch_dev = NULL;
 	spin_unlock(&mchdev_lock);
 
+	mutex_lock(&dev->struct_mutex);
+	ret = i915_gpu_idle(dev);
+	if (ret)
+		DRM_ERROR("failed to idle hardware: %d\n", ret);
+	mutex_unlock(&dev->struct_mutex);
+
 	io_mapping_free(dev_priv->mm.gtt_mapping);
 	if (dev_priv->mm.gtt_mtrr >= 0) {
 		mtrr_del(dev_priv->mm.gtt_mtrr, dev->agp->base,
@@ -2303,7 +2310,6 @@ int i915_driver_unload(struct drm_device *dev)
 		if (I915_HAS_FBC(dev) && i915_powersave)
 			i915_cleanup_compression(dev);
 		drm_mm_takedown(&dev_priv->vram);
-		i915_gem_lastclose(dev);
 
 		intel_cleanup_overlay(dev);
 	}