DAHDI: Print error message in case config uses non-existing span
diff --git a/src/input/dahdi.c b/src/input/dahdi.c
index 9fb0304..b7382a7 100644
--- a/src/input/dahdi.c
+++ b/src/input/dahdi.c
@@ -447,8 +447,12 @@
 	reread_span_cfgs();
 
 	scfg = span_cfgs[line->port_nr];
-	if (!scfg)
+	if (!scfg) {
+		LOGP(DLMI, LOGL_ERROR, "Line %u(%s): DAHDI Port %u (Span %u) "
+			"doesn't exist\n", line->num, line->name, line->port_nr,
+			line->port_nr+1);
 		return -EIO;
+	}
 
 	line->num_ts = scfg->chan_num;