drm/i915: Handle drm_atomic_helper_swap_state failure

drm_atomic_helper_swap_state() will be changed to interruptible waiting
in the next few commits, so all drivers have to be changed to handling
failure.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170711143314.2148-6-maarten.lankhorst@linux.intel.com
Reviewed-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -13271,7 +13271,15 @@ static int intel_atomic_commit(struct drm_device *dev,
 	if (INTEL_GEN(dev_priv) < 9)
 		state->legacy_cursor_update = false;
 
-	drm_atomic_helper_swap_state(state, true);
+	ret = drm_atomic_helper_swap_state(state, true);
+	if (ret) {
+		i915_sw_fence_commit(&intel_state->commit_ready);
+
+		mutex_lock(&dev->struct_mutex);
+		drm_atomic_helper_cleanup_planes(dev, state);
+		mutex_unlock(&dev->struct_mutex);
+		return ret;
+	}
 	dev_priv->wm.distrust_bios_wm = false;
 	intel_shared_dpll_swap_state(state);
 	intel_atomic_track_fbs(state);