diff --git a/sys/dev/cxgbe/t4_main.c b/sys/dev/cxgbe/t4_main.c
index 338e357fe02..6e4dd4b01a7 100644
--- a/sys/dev/cxgbe/t4_main.c
+++ b/sys/dev/cxgbe/t4_main.c
@@ -455,7 +455,7 @@ TUNABLE_INT("hw.cxgbe.iscsicaps_allowed", &t4_iscsicaps_allowed);
 static int t4_fcoecaps_allowed = 0;
 TUNABLE_INT("hw.cxgbe.fcoecaps_allowed", &t4_fcoecaps_allowed);
 
-static int t5_write_combine = 1;
+static int t5_write_combine = 0;
 TUNABLE_INT("hw.cxl.write_combine", &t5_write_combine);
 
 static int t4_num_vis = 1;
@@ -2292,7 +2292,6 @@ t4_map_bar_2(struct adapter *sc)
 				setbit(&sc->doorbells, DOORBELL_WCWR);
 				setbit(&sc->doorbells, DOORBELL_UDBWC);
 			} else {
-				t5_write_combine = 0;
 				device_printf(sc->dev,
 				    "couldn't enable write combining: %d\n",
 				    rc);
@@ -2302,11 +2301,9 @@ t4_map_bar_2(struct adapter *sc)
 			t4_write_reg(sc, A_SGE_STAT_CFG,
 			    V_STATSOURCE_T5(7) | mode);
 		}
-#else
-		t5_write_combine = 0;
 #endif
-		sc->iwt.wc_en = t5_write_combine;
 	}
+	sc->iwt.wc_en = isset(&sc->doorbells, DOORBELL_UDBWC) ? 1 : 0;
 
 	return (0);
 }