drm/i915: Convert connector checking to atomic, v3.

Right now dpms callbacks can still fiddle with the connector state,
but it can only turn connectors off.

This is remediated by only checking crtc->state->active when the
connector is active, and ignore crtc->state->active when the
connector is off.

connectors_active is no longer checked, and will be removed later
in this series together with dpms.

Another check for !encoder->crtc is performed by check_encoder_state
too, so it can be removed.

Changes since v1:
- Add commit message.
- rename state to old_state.
- Move deletion of mst_port check to mst patch.
Changes since v2:
- Fix a null pointer dereference on MST now hw readout is fixed.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_display.c

@@ -6362,38 +6362,36 @@ static void intel_encoder_dpms(struct intel_encoder *encoder, int mode)
  * internal consistency). */
 static void intel_connector_check_state(struct intel_connector *connector)
 {
+	struct drm_crtc *crtc = connector->base.state->crtc;
+
+	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
+		      connector->base.base.id,
+		      connector->base.name);
+
 	if (connector->get_hw_state(connector)) {
-		struct intel_encoder *encoder = connector->encoder;
-		struct drm_crtc *crtc;
-		bool encoder_enabled;
-		enum pipe pipe;
+		struct drm_encoder *encoder = &connector->encoder->base;
+		struct drm_connector_state *conn_state = connector->base.state;
 
-		DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
-			      connector->base.base.id,
-			      connector->base.name);
+		I915_STATE_WARN(!crtc,
+			 "connector enabled without attached crtc\n");
 
-		I915_STATE_WARN(connector->base.dpms == DRM_MODE_DPMS_OFF,
-		     "wrong connector dpms state\n");
-		I915_STATE_WARN(connector->base.encoder != &encoder->base,
-		     "active connector not linked to encoder\n");
+		if (!crtc)
+			return;
 
-		if (encoder) {
-			I915_STATE_WARN(!encoder->connectors_active,
-			     "encoder->connectors_active not set\n");
+		I915_STATE_WARN(!crtc->state->active,
+		      "connector is active, but attached crtc isn't\n");
 
-			encoder_enabled = encoder->get_hw_state(encoder, &pipe);
-			I915_STATE_WARN(!encoder_enabled, "encoder not enabled\n");
-			if (I915_STATE_WARN_ON(!encoder->base.crtc))
-				return;
+		if (!encoder)
+			return;
 
-			crtc = encoder->base.crtc;
+		I915_STATE_WARN(conn_state->best_encoder != encoder,
+			"atomic encoder doesn't match attached encoder\n");
 
-			I915_STATE_WARN(!crtc->state->enable,
-					"crtc not enabled\n");
-			I915_STATE_WARN(!to_intel_crtc(crtc)->active, "crtc not active\n");
-			I915_STATE_WARN(pipe != to_intel_crtc(crtc)->pipe,
-			     "encoder active on the wrong pipe\n");
-		}
+		I915_STATE_WARN(conn_state->crtc != encoder->crtc,
+			"attached encoder crtc differs from connector crtc\n");
+	} else {
+		I915_STATE_WARN(!crtc && connector->base.state->best_encoder,
+			"best encoder set without crtc!\n");
 	}
 }
 
@@ -12698,20 +12696,23 @@ static void check_wm_state(struct drm_device *dev)
 }
 
 static void
-check_connector_state(struct drm_device *dev)
+check_connector_state(struct drm_device *dev,
+		      struct drm_atomic_state *old_state)
 {
-	struct intel_connector *connector;
+	struct drm_connector_state *old_conn_state;
+	struct drm_connector *connector;
+	int i;
 
-	for_each_intel_connector(dev, connector) {
-		struct drm_encoder *encoder = connector->base.encoder;
-		struct drm_connector_state *state = connector->base.state;
+	for_each_connector_in_state(old_state, connector, old_conn_state, i) {
+		struct drm_encoder *encoder = connector->encoder;
+		struct drm_connector_state *state = connector->state;
 
 		/* This also checks the encoder/connector hw state with the
 		 * ->get_hw_state callbacks. */
-		intel_connector_check_state(connector);
+		intel_connector_check_state(to_intel_connector(connector));
 
 		I915_STATE_WARN(state->best_encoder != encoder,
-		     "connector's staged encoder doesn't match current encoder\n");
+		     "connector's atomic encoder doesn't match legacy encoder\n");
 	}
 }
 
@@ -12902,7 +12903,7 @@ intel_modeset_check_state(struct drm_device *dev,
 			  struct drm_atomic_state *old_state)
 {
 	check_wm_state(dev);
-	check_connector_state(dev);
+	check_connector_state(dev, old_state);
 	check_encoder_state(dev);
 	check_crtc_state(dev);
 	check_shared_dpll_state(dev);