openwrt/target/linux/bcm27xx/patches-5.10/950-0082-net-lan78xx-Disable-TCP-Segmentation-Offload-TSO.patch
John Audia 6b1cd3e345 kernel: bump 5.10 to 5.10.61
Manually rebased:
  bcm27xx/patches-5.10/950-1031-net-lan78xx-Ack-pending-PHY-ints-when-resetting.patch

Removed upstreamed:
  mvebu/patches-5.10/101-cpufreq-armada-37xx-forbid-cpufreq-for-1.2-GHz-variant.patch

All other patches automatically rebased.

Build system: x86_64
Build-tested: bcm2711/RPi4B
Run-tested: bcm2711/RPi4B

No dmesg regressions, everything functional

Signed-off-by: John Audia <graysky@archlinux.us>
2021-08-29 16:30:20 +02:00

57 lines
2.1 KiB
Diff

From 42606db546588b0e0b8084466b9b31ec111640a4 Mon Sep 17 00:00:00 2001
From: Dave Stevenson <dave.stevenson@raspberrypi.org>
Date: Wed, 13 Jun 2018 15:21:10 +0100
Subject: [PATCH] net: lan78xx: Disable TCP Segmentation Offload (TSO)
TSO seems to be having issues when packets are dropped and the
remote end uses Selective Acknowledge (SACK) to denote that
data is missing. The missing data is never resent, so the
connection eventually stalls.
There is a module parameter of enable_tso added to allow
further debugging without forcing a rebuild of the kernel.
https://github.com/raspberrypi/linux/issues/2449
https://github.com/raspberrypi/linux/issues/2482
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
---
drivers/net/usb/lan78xx.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
--- a/drivers/net/usb/lan78xx.c
+++ b/drivers/net/usb/lan78xx.c
@@ -425,6 +425,15 @@ static int msg_level = -1;
module_param(msg_level, int, 0);
MODULE_PARM_DESC(msg_level, "Override default message level");
+/* TSO seems to be having some issue with Selective Acknowledge (SACK) that
+ * results in lost data never being retransmitted.
+ * Disable it by default now, but adds a module parameter to enable it for
+ * debug purposes (the full cause is not currently understood).
+ */
+static bool enable_tso;
+module_param(enable_tso, bool, 0644);
+MODULE_PARM_DESC(enable_tso, "Enables TCP segmentation offload");
+
static int lan78xx_read_reg(struct lan78xx_net *dev, u32 index, u32 *data)
{
u32 *buf = kmalloc(sizeof(u32), GFP_KERNEL);
@@ -2925,8 +2934,14 @@ static int lan78xx_bind(struct lan78xx_n
if (DEFAULT_RX_CSUM_ENABLE)
dev->net->features |= NETIF_F_RXCSUM;
- if (DEFAULT_TSO_CSUM_ENABLE)
- dev->net->features |= NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_SG;
+ if (DEFAULT_TSO_CSUM_ENABLE) {
+ dev->net->features |= NETIF_F_SG;
+ /* Use module parameter to control TCP segmentation offload as
+ * it appears to cause issues.
+ */
+ if (enable_tso)
+ dev->net->features |= NETIF_F_TSO | NETIF_F_TSO6;
+ }
if (DEFAULT_VLAN_RX_OFFLOAD)
dev->net->features |= NETIF_F_HW_VLAN_CTAG_RX;