Index: sys/net/iflib.c
===================================================================
--- sys/net/iflib.c
+++ sys/net/iflib.c
@@ -4385,6 +4385,12 @@
 				      i, scctx->isc_nrxd[i], sctx->isc_nrxd_max[i]);
 			scctx->isc_nrxd[i] = sctx->isc_nrxd_max[i];
 		}
+		if (!powerof2(scctx->isc_nrxd[i])) {
+			int rounded = 1 << (fls(scctx->isc_nrxd[i]) - 1);
+			device_printf(dev, "nrxd%d: %d is not a power of 2 - rounding down to %d\n",
+				      i, scctx->isc_nrxd[i], rounded);
+			scctx->isc_nrxd[i] = rounded;
+		}
 	}
 
 	for (i = 0; i < sctx->isc_ntxqs; i++) {
@@ -4398,6 +4404,12 @@
 				      i, scctx->isc_ntxd[i], sctx->isc_ntxd_max[i]);
 			scctx->isc_ntxd[i] = sctx->isc_ntxd_max[i];
 		}
+		if (!powerof2(scctx->isc_ntxd[i])) {
+			int rounded = 1 << (fls(scctx->isc_ntxd[i]) - 1);
+			device_printf(dev, "ntxd%d: %d is not a power of 2 - rounding down to %d\n",
+				      i, scctx->isc_ntxd[i], rounded);
+			scctx->isc_ntxd[i] = rounded;
+		}
 	}
 }
 
@@ -4408,7 +4420,6 @@
 	if_ctx_t ctx;
 	if_t ifp;
 	if_softc_ctx_t scctx;
-	int i;
 	uint16_t main_txq;
 	uint16_t main_rxq;
 
@@ -4463,22 +4474,6 @@
 	/* XXX change for per-queue sizes */
 	device_printf(dev, "Using %d tx descriptors and %d rx descriptors\n",
 	    scctx->isc_ntxd[main_txq], scctx->isc_nrxd[main_rxq]);
-	for (i = 0; i < sctx->isc_nrxqs; i++) {
-		if (!powerof2(scctx->isc_nrxd[i])) {
-			/* round down instead? */
-			device_printf(dev, "# rx descriptors must be a power of 2\n");
-			err = EINVAL;
-			goto fail_iflib_detach;
-		}
-	}
-	for (i = 0; i < sctx->isc_ntxqs; i++) {
-		if (!powerof2(scctx->isc_ntxd[i])) {
-			device_printf(dev,
-			    "# tx descriptors must be a power of 2");
-			err = EINVAL;
-			goto fail_iflib_detach;
-		}
-	}
 
 	if (scctx->isc_tx_nsegments > scctx->isc_ntxd[main_txq] /
 	    MAX_SINGLE_PACKET_FRACTION)
@@ -4615,7 +4610,6 @@
 fail_queues:
 	iflib_tx_structures_free(ctx);
 	iflib_rx_structures_free(ctx);
-fail_iflib_detach:
 	IFDI_DETACH(ctx);
 fail_unlock:
 	CTX_UNLOCK(ctx);
@@ -4658,9 +4652,6 @@
 	scctx = &ctx->ifc_softc_ctx;
 	ifp = ctx->ifc_ifp;
 
-	/*
-	 * XXX sanity check that ntxd & nrxd are a power of 2
-	 */
 	iflib_reset_qvalues(ctx);
 	CTX_LOCK(ctx);
 	if ((err = IFDI_ATTACH_PRE(ctx)) != 0) {
@@ -4725,22 +4716,6 @@
 	/* XXX change for per-queue sizes */
 	device_printf(dev, "Using %d tx descriptors and %d rx descriptors\n",
 	    scctx->isc_ntxd[main_txq], scctx->isc_nrxd[main_rxq]);
-	for (i = 0; i < sctx->isc_nrxqs; i++) {
-		if (!powerof2(scctx->isc_nrxd[i])) {
-			/* round down instead? */
-			device_printf(dev, "# rx descriptors must be a power of 2\n");
-			err = EINVAL;
-			goto fail_iflib_detach;
-		}
-	}
-	for (i = 0; i < sctx->isc_ntxqs; i++) {
-		if (!powerof2(scctx->isc_ntxd[i])) {
-			device_printf(dev,
-			    "# tx descriptors must be a power of 2");
-			err = EINVAL;
-			goto fail_iflib_detach;
-		}
-	}
 
 	if (scctx->isc_tx_nsegments > scctx->isc_ntxd[main_txq] /
 	    MAX_SINGLE_PACKET_FRACTION)