drm/i915: Use atomic helpers for suspend, v2.

Instead of duplicating the functionality now that we no longer need
to preserve dpll state we can move to using the upstream suspend helper.

Changes since v1:
- Call hw readout with all mutexes held.
- Rework intel_display_suspend to only assign modeset_restore_state
  on success.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/56C2E686.5060803@linux.intel.com
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

drivers/gpu/drm/i915/i915_drv.c

@@ -603,13 +603,7 @@ static int i915_drm_suspend(struct drm_device *dev)
 
 	intel_suspend_gt_powersave(dev);
 
-	/*
-	 * Disable CRTCs directly since we want to preserve sw state
-	 * for _thaw. Also, power gate the CRTC power wells.
-	 */
-	drm_modeset_lock_all(dev);
 	intel_display_suspend(dev);
-	drm_modeset_unlock_all(dev);
 
 	intel_dp_mst_suspend(dev);
 
@@ -764,9 +758,7 @@ static int i915_drm_resume(struct drm_device *dev)
 		dev_priv->display.hpd_irq_setup(dev);
 	spin_unlock_irq(&dev_priv->irq_lock);
 
-	drm_modeset_lock_all(dev);
 	intel_display_resume(dev);
-	drm_modeset_unlock_all(dev);
 
 	intel_dp_mst_resume(dev);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -1848,6 +1848,7 @@ struct drm_i915_private {
 
 	enum modeset_restore modeset_restore;
 	struct mutex modeset_restore_lock;
+	struct drm_atomic_state *modeset_restore_state;
 
 	struct list_head vm_list; /* Global list of all address spaces */
 	struct i915_gtt gtt; /* VM representing the global address space */

drivers/gpu/drm/i915/intel_display.c

@@ -6397,55 +6397,16 @@ static void intel_crtc_disable_noatomic(struct drm_crtc *crtc)
  */
 int intel_display_suspend(struct drm_device *dev)
 {
-	struct drm_mode_config *config = &dev->mode_config;
-	struct drm_modeset_acquire_ctx *ctx = config->acquire_ctx;
+	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct drm_atomic_state *state;
-	struct drm_crtc *crtc;
-	unsigned crtc_mask = 0;
-	int ret = 0;
+	int ret;
 
-	if (WARN_ON(!ctx))
-		return 0;
-
-	lockdep_assert_held(&ctx->ww_ctx);
-	state = drm_atomic_state_alloc(dev);
-	if (WARN_ON(!state))
-		return -ENOMEM;
-
-	state->acquire_ctx = ctx;
-	state->allow_modeset = true;
-
-	for_each_crtc(dev, crtc) {
-		struct drm_crtc_state *crtc_state =
-			drm_atomic_get_crtc_state(state, crtc);
-
-		ret = PTR_ERR_OR_ZERO(crtc_state);
-		if (ret)
-			goto free;
-
-		if (!crtc_state->active)
-			continue;
-
-		crtc_state->active = false;
-		crtc_mask |= 1 << drm_crtc_index(crtc);
-	}
-
-	if (crtc_mask) {
-		ret = drm_atomic_commit(state);
-
-		if (!ret) {
-			for_each_crtc(dev, crtc)
-				if (crtc_mask & (1 << drm_crtc_index(crtc)))
-					crtc->state->active = true;
-
-			return ret;
-		}
-	}
-
-free:
+	state = drm_atomic_helper_suspend(dev);
+	ret = PTR_ERR_OR_ZERO(state);
 	if (ret)
 		DRM_ERROR("Suspending crtc's failed with %i\n", ret);
-	drm_atomic_state_free(state);
+	else
+		dev_priv->modeset_restore_state = state;
 	return ret;
 }
 
@@ -15918,51 +15879,57 @@ intel_modeset_setup_hw_state(struct drm_device *dev)
 
 void intel_display_resume(struct drm_device *dev)
 {
-	struct drm_atomic_state *state = drm_atomic_state_alloc(dev);
-	struct intel_connector *conn;
-	struct intel_plane *plane;
-	struct drm_crtc *crtc;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct drm_atomic_state *state = dev_priv->modeset_restore_state;
+	struct drm_modeset_acquire_ctx ctx;
 	int ret;
+	bool setup = false;
 
-	if (!state)
-		return;
+	dev_priv->modeset_restore_state = NULL;
 
-	state->acquire_ctx = dev->mode_config.acquire_ctx;
+	drm_modeset_acquire_init(&ctx, 0);
 
-	for_each_crtc(dev, crtc) {
-		struct drm_crtc_state *crtc_state =
-			drm_atomic_get_crtc_state(state, crtc);
+retry:
+	ret = drm_modeset_lock_all_ctx(dev, &ctx);
 
-		ret = PTR_ERR_OR_ZERO(crtc_state);
-		if (ret)
-			goto err;
+	if (ret == 0 && !setup) {
+		setup = true;
 
-		/* force a restore */
-		crtc_state->mode_changed = true;
+		intel_modeset_setup_hw_state(dev);
+		i915_redisable_vga(dev);
 	}
 
-	for_each_intel_plane(dev, plane) {
-		ret = PTR_ERR_OR_ZERO(drm_atomic_get_plane_state(state, &plane->base));
-		if (ret)
-			goto err;
+	if (ret == 0 && state) {
+		struct drm_crtc_state *crtc_state;
+		struct drm_crtc *crtc;
+		int i;
+
+		state->acquire_ctx = &ctx;
+
+		for_each_crtc_in_state(state, crtc, crtc_state, i) {
+			/*
+			 * Force recalculation even if we restore
+			 * current state. With fast modeset this may not result
+			 * in a modeset when the state is compatible.
+			 */
+			crtc_state->mode_changed = true;
+		}
+
+		ret = drm_atomic_commit(state);
 	}
 
-	for_each_intel_connector(dev, conn) {
-		ret = PTR_ERR_OR_ZERO(drm_atomic_get_connector_state(state, &conn->base));
-		if (ret)
-			goto err;
+	if (ret == -EDEADLK) {
+		drm_modeset_backoff(&ctx);
+		goto retry;
 	}
 
-	intel_modeset_setup_hw_state(dev);
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
 
-	i915_redisable_vga(dev);
-	ret = drm_atomic_commit(state);
-	if (!ret)
-		return;
-
-err:
-	DRM_ERROR("Restoring old state failed with %i\n", ret);
-	drm_atomic_state_free(state);
+	if (ret) {
+		DRM_ERROR("Restoring old state failed with %i\n", ret);
+		drm_atomic_state_free(state);
+	}
 }
 
 void intel_modeset_gem_init(struct drm_device *dev)