drm/i915/mst: use reference counted connectors. (v3)

Don't just free the connector when we get the destroy callback.

Drop a reference to it, and set it's mst_port to NULL so
no more mst work is done on it.

v2: core mst accepts NULLs fine. Cleanup EDID code properly.
v3: drop the extra reference we were taking.

Reviewed-by: Daniel Vetter <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>

drivers/gpu/drm/i915/intel_dp_mst.c

···
 
 	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
 
-	drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, intel_mst->port);
+	drm_dp_mst_reset_vcpi_slots(&intel_dp->mst_mgr, intel_mst->connector->port);
 
 	ret = drm_dp_update_payload_part1(&intel_dp->mst_mgr);
 	if (ret) {
···
 	/* and this can also fail */
 	drm_dp_update_payload_part2(&intel_dp->mst_mgr);
 
-	drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, intel_mst->port);
+	drm_dp_mst_deallocate_vcpi(&intel_dp->mst_mgr, intel_mst->connector->port);
 
 	intel_dp->active_mst_links--;
-	intel_mst->port = NULL;
+
+	intel_mst->connector = NULL;
 	if (intel_dp->active_mst_links == 0) {
 		intel_dig_port->base.post_disable(&intel_dig_port->base);
 		intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF);
···
 	found->encoder = encoder;
 
 	DRM_DEBUG_KMS("%d\n", intel_dp->active_mst_links);
-	intel_mst->port = found->port;
+
+	intel_mst->connector = found;
 
 	if (intel_dp->active_mst_links == 0) {
 		intel_prepare_ddi_buffer(&intel_dig_port->base);
···
 	}
 
 	ret = drm_dp_mst_allocate_vcpi(&intel_dp->mst_mgr,
-				       intel_mst->port,
+				       intel_mst->connector->port,
 				       intel_crtc->config->pbn, &slots);
 	if (ret == false) {
 		DRM_ERROR("failed to allocate vcpi\n");
···
 {
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(&encoder->base);
 	*pipe = intel_mst->pipe;
-	if (intel_mst->port)
+	if (intel_mst->connector)
 		return true;
 	return false;
 }
···
 	struct edid *edid;
 	int ret;
 
-	edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
-	if (!edid)
-		return 0;
+	if (!intel_dp) {
+		return intel_connector_update_modes(connector, NULL);
+	}
 
+	edid = drm_dp_mst_get_edid(connector, &intel_dp->mst_mgr, intel_connector->port);
 	ret = intel_connector_update_modes(connector, edid);
 	kfree(edid);
 
···
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	struct intel_dp *intel_dp = intel_connector->mst_port;
 
+	if (!intel_dp)
+		return connector_status_disconnected;
 	return drm_dp_mst_detect_port(connector, &intel_dp->mst_mgr, intel_connector->port);
 }
 
···
 	struct intel_dp *intel_dp = intel_connector->mst_port;
 	struct intel_crtc *crtc = to_intel_crtc(state->crtc);
 
+	if (!intel_dp)
+		return NULL;
 	return &intel_dp->mst_encoders[crtc->pipe]->base.base;
 }
 
···
 {
 	struct intel_connector *intel_connector = to_intel_connector(connector);
 	struct intel_dp *intel_dp = intel_connector->mst_port;
+	if (!intel_dp)
+		return NULL;
 	return &intel_dp->mst_encoders[0]->base.base;
 }
 
···
 
 	/* need to nuke the connector */
 	drm_modeset_lock_all(dev);
-	if (connector->state->crtc) {
-		struct drm_mode_set set;
-		int ret;
-
-		memset(&set, 0, sizeof(set));
-		set.crtc = connector->state->crtc,
-
-		ret = drm_atomic_helper_set_config(&set);
-
-		WARN(ret, "Disabling mst crtc failed with %i\n", ret);
-	}
-
 	intel_connector_remove_from_fbdev(intel_connector);
-	drm_connector_cleanup(connector);
+	intel_connector->mst_port = NULL;
 	drm_modeset_unlock_all(dev);
 
-	kfree(intel_connector);
+	drm_connector_unreference(&intel_connector->base);
 	DRM_DEBUG_KMS("\n");
 }
 

drivers/gpu/drm/i915/intel_drv.h

···
 	struct intel_encoder base;
 	enum pipe pipe;
 	struct intel_digital_port *primary;
-	void *port; /* store this opaque as its illegal to dereference it */
+	struct intel_connector *connector;
 };
 
 static inline enum dpio_channel