diff --git a/sys/dev/tws/tws.c b/sys/dev/tws/tws.c
--- a/sys/dev/tws/tws.c
+++ b/sys/dev/tws/tws.c
@@ -349,7 +349,7 @@
 {
     struct tws_softc *sc = device_get_softc(dev);
     int i;
-    u_int32_t reg __diagused;
+    u_int32_t reg __tws_debug;
 
     TWS_TRACE_DEBUG(sc, "entry", 0, 0);
 
diff --git a/sys/dev/tws/tws_hdm.c b/sys/dev/tws/tws_hdm.c
--- a/sys/dev/tws/tws_hdm.c
+++ b/sys/dev/tws/tws_hdm.c
@@ -82,7 +82,7 @@
 int 
 tws_init_ctlr(struct tws_softc *sc)
 {
-    u_int64_t reg __diagused;
+    u_int64_t reg __tws_debug;
     u_int32_t regh, regl;
 
     TWS_TRACE_DEBUG(sc, "entry", sc, sc->is64bit);
diff --git a/sys/dev/tws/tws_services.h b/sys/dev/tws/tws_services.h
--- a/sys/dev/tws/tws_services.h
+++ b/sys/dev/tws/tws_services.h
@@ -61,10 +61,12 @@
 #endif
 
 #ifdef TWS_TRACE_DEBUG_ON
+    #define __tws_debug
     #define TWS_TRACE_DEBUG(sc, desc, val1, val2) \
             tws_trace(__FILE__, __func__, __LINE__, sc, desc, \
                                    (u_int64_t)val1, (u_int64_t)val2)
 #else
+    #define __tws_debug __unused
     #define TWS_TRACE_DEBUG(sc, desc, val1, val2)
 #endif