diff --git a/rtl/common.vh b/rtl/common.vh
index 108bb58..161b4d0 100644
--- a/rtl/common.vh
+++ b/rtl/common.vh
@@ -7,14 +7,14 @@
 `define COMMON_VH
 
 `ifdef SYNTHESIS
-`define DUMP
+`define DUMP(levels)
 `else
-`define DUMP \
+`define DUMP(levels) \
 	reg [4096:0] vcdfile; \
 	initial begin \
 		if ($value$plusargs("vcd=%s", vcdfile)) begin \
 			$dumpfile(vcdfile); \
-			$dumpvars; \
+			$dumpvars(levels); \
 		end \
 	end
 `endif
diff --git a/rtl/pcs.v b/rtl/pcs.v
index edef284..216f6a1 100644
--- a/rtl/pcs.v
+++ b/rtl/pcs.v
@@ -92,7 +92,7 @@ module pcs (
 	assign col = transmitting && receiving;
 	assign crs = transmitting || receiving;
 
-	`DUMP
+	`DUMP(0)
 
 endmodule
 
diff --git a/rtl/pmd.v b/rtl/pmd.v
index 244d1cc..28b98b1 100644
--- a/rtl/pmd.v
+++ b/rtl/pmd.v
@@ -225,6 +225,6 @@ module pmd (
 	end
 `endif
 
-	`DUMP
+	`DUMP(0)
 
 endmodule