try harder to leave a gap on the tx ring.

i think before this change we could overwrite entries on the ring,
which can confuse the chip and the tx completion code. i think.
it's funny how much a comparison hurts my brain.

ok patrick@
tested by and ok kevlo@

2 files changed, 4 insertions, 4 deletions

diff --git a/sys/dev/ic/re.c b/sys/dev/ic/re.c
index 29074188922..a8967f686df 100644
--- a/sys/dev/ic/re.c
+++ b/sys/dev/ic/re.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: re.c,v 1.217 2024/01/19 03:46:14 dlg Exp $	*/
+/*	$OpenBSD: re.c,v 1.218 2024/08/12 06:47:11 dlg Exp $	*/
 /*	$FreeBSD: if_re.c,v 1.31 2004/09/04 07:54:05 ru Exp $	*/
 /*
  * Copyright (c) 1997, 1998-2003
@@ -1834,7 +1834,7 @@ re_start(struct ifqueue *ifq)
 	free -= idx;
 
 	for (;;) {
-		if (sc->rl_ldata.rl_tx_ndescs >= free + 2) {
+		if (free < sc->rl_ldata.rl_tx_ndescs + 2) {
 			ifq_set_oactive(ifq);
 			break;
 		}
diff --git a/sys/dev/pci/if_rge.c b/sys/dev/pci/if_rge.c
index b6ba51494d5..4309f2cdf46 100644
--- a/sys/dev/pci/if_rge.c
+++ b/sys/dev/pci/if_rge.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_rge.c,v 1.28 2024/08/10 21:53:06 patrick Exp $	*/
+/*	$OpenBSD: if_rge.c,v 1.29 2024/08/12 06:47:11 dlg Exp $	*/
 
 /*
  * Copyright (c) 2019, 2020, 2023, 2024
@@ -581,7 +581,7 @@ rge_start(struct ifqueue *ifq)
 	free -= idx;
 
 	for (;;) {
-		if (RGE_TX_NSEGS >= free + 2) {
+		if (free < RGE_TX_NSEGS + 2) {
 			ifq_set_oactive(&ifp->if_snd);
 			break;
 		}