Index: trunk/src/plugins/rt_topo/crbs.c
===================================================================
--- trunk/src/plugins/rt_topo/crbs.c	(revision 1321)
+++ trunk/src/plugins/rt_topo/crbs.c	(revision 1322)
@@ -41,9 +41,9 @@
 static void crbs_coll_report_cb(grbs_t *grbs, grbs_2net_t *tn, grbs_2net_t *coll_tn, grbs_arc_t *coll_arc)
 {
 	crbs_t *crbs = grbs->user_data;
-	crbs_2net_t *ctn = tn->user_data, *coll_ctn = coll_tn->user_data;
+	crbs_2net_t *coll_ctn = coll_tn->user_data;
+/*	crbs_2net_t *ctn = tn->user_data;*/
 
-	printf("\n(COLLISION %s %s)\n", ctn->tn->net->hdr.oid, coll_ctn->tn->net->hdr.oid);
 	htpi_set(&crbs->coll_nets, coll_ctn, 1);
 }
 
Index: trunk/src/plugins/rt_topo/crbs.h
===================================================================
--- trunk/src/plugins/rt_topo/crbs.h	(revision 1321)
+++ trunk/src/plugins/rt_topo/crbs.h	(revision 1322)
@@ -26,8 +26,9 @@
 typedef struct {
 	point_t *cstart, *cend;
 	rt_topo_2net_t *tn;
+	grbs_2net_t *gtn;
+	unsigned int ripped_up; /* how many times this net got ripped up */
 	gdl_elem_t link;
-	unsigned int ripped_up; /* how many times this net got ripped up */
 } crbs_2net_t;
 
 typedef struct crbs_point_s {
@@ -50,6 +51,7 @@
 	void *first_mark, *target_mark;
 	grbs_2net_t *routing_tn;
 	htpi_t coll_nets; /* nets routing_tn has collided with; indexed with (crbs_2net_t *) */
+	int max_ripup; /* how many times are we willing to rip up a 2net (total within a layer routing) */
 } crbs_t;
 
 int rt_topo_crbs(rtrnd_t *ctx, rt_topo_laa2rbs_t *src);
Index: trunk/src/plugins/rt_topo/crbs_route.c
===================================================================
--- trunk/src/plugins/rt_topo/crbs_route.c	(revision 1321)
+++ trunk/src/plugins/rt_topo/crbs_route.c	(revision 1322)
@@ -343,8 +343,12 @@
 	crbs->target = ast.target = addr_new_point(crbs, ctn->cend, &addr_tmp[1]);
 
 #warning TODO: per net wire thickness
-	crbs->routing_tn = grbs_2net_new(&crbs->grbs, rt_topo_cfg.wire_thick, rt_topo_cfg.wire_clr);
-	crbs->routing_tn->user_data = ctn;
+	if (ctn->gtn == NULL) {
+		crbs->routing_tn = ctn->gtn = grbs_2net_new(&crbs->grbs, rt_topo_cfg.wire_thick, rt_topo_cfg.wire_clr);
+		crbs->routing_tn->user_data = ctn;
+	}
+	else
+		crbs->routing_tn = ctn->gtn;
 
 	printf(" route_net: from P%ld to P%ld\n",
 		((crbs_point_t *)(ctn->cstart->data))->gpt->uid,
@@ -425,14 +429,39 @@
 	return res;
 }
 
-static void on_fail_ripup(crbs_t *crbs, crbs_2net_t *tn)
+/* Returns 1 if ripped up something */
+static int on_fail_ripup(crbs_t *crbs, crbs_2net_t *tn)
 {
 	htpi_entry_t *e;
-	printf(" !!!!!!!!Failed to route; checking what to rip up:\n");
+	int best_r = crbs->max_ripup;
+	crbs_2net_t *best = NULL;
+
+	printf(" Failed to route; checking what to rip up:\n");
+
 	for(e = htpi_first(&crbs->coll_nets); e != NULL; e = htpi_next(&crbs->coll_nets, e)) {
 		crbs_2net_t *ctn = e->key;
 		printf("  %s (%d)\n", ctn->tn->net->hdr.oid, ctn->ripped_up);
+		if (ctn->ripped_up < best_r) {
+			best_r = ctn->ripped_up;
+			best = ctn;
+		}
 	}
+
+	if (best == NULL)
+		return 0; /* nothing to rip up */
+
+	printf(" ripping up %s\n", best->tn->net->hdr.oid);
+
+	/* remove the offending 2net */
+	best->ripped_up++;
+	grbs_path_remove_2net(&crbs->grbs, best->gtn);
+	best->gtn = NULL;
+
+	/* re-schedule it to after tn */
+	gdl_remove(&crbs->twonets, best, link);
+	gdl_insert_after(&crbs->twonets, tn, best, link);
+
+	return 1;
 }
 
 static int rt_topo_crbs_layer_(rtrnd_t *ctx, crbs_t *crbs, rtrnd_layer_t *ly, long attempt, rtrnd_layer_t *ly_cdt, rtrnd_layer_t *ly_bnk)
@@ -450,13 +479,16 @@
 	rtrnd_export(ctx, "svg", fn, NULL, &annot);
 
 	/* route all nets */
-	for(ttn = gdl_first(&crbs->twonets); ttn != NULL; ttn = gdl_next(&crbs->twonets, ttn)) {
+	for(ttn = gdl_first(&crbs->twonets); ttn != NULL; ) {
 		printf("CRBS route net %s:\n", ttn->tn->net->hdr.oid);
 		if (rt_topo_crbs_route_net(crbs, ttn) != 0) {
-			on_fail_ripup(crbs, ttn);
-			res = 1;
-			break;
+			if (on_fail_ripup(crbs, ttn))
+				continue; /* ripped up another net, retry with ttn */
+			/* else: coudln't find anything to rip up or ripup count is too high
+			   already: give up routing this net */
+			printf(" => Giving up routing %s\n", ttn->tn->net->hdr.oid);
 		}
+		ttn = gdl_next(&crbs->twonets, ttn);
 	}
 
 	rtrnd_layer_init(&ly_neighb, "neighb");
@@ -495,6 +527,7 @@
 	strcpy(ly_bnk.color, "#6666aa");
 
 	/* convert input twonets to crbs twonets, making sure they have endpoints in the cdt */
+	crbs.max_ripup = 0;
 	for(t = gdl_first(tnl); t != NULL; t = t->link.next) {
 		crbs_2net_t *ct = calloc(sizeof(crbs_2net_t), 1);
 		ct->cstart = cdt_insert_point(&crbs.cdt, t->x[0], t->y[0]);
@@ -501,6 +534,7 @@
 		ct->cend = cdt_insert_point(&crbs.cdt, t->x[1], t->y[1]);
 		ct->tn = t;
 		gdl_append(&crbs.twonets, ct, link);
+		crbs.max_ripup++;
 	}
 
 	rt_topo_crbs_cdt_draw(ctx, &ly_cdt, &crbs.cdt);