[PATCH net 5.7] r8169: change back SG and TSO to be disabled by default

[PATCH net 5.7] r8169: change back SG and TSO to be disabled by default

[Heiner Kallweit]

There has been a number of reports that using SG/TSO on different chip
versions results in tx timeouts. However for a lot of people SG/TSO
works fine. Therefore disable both features by default, but allow users
to enable them. Use at own risk!

Fixes: 93681cd7d94f ("r8169: enable HW csum and TSO")
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
This version of the fix applies on 5.7.
---
 drivers/net/ethernet/realtek/r8169_main.c | 29 +++++++++++------------
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
index 55cb5730b..bf5bf0597 100644
--- a/drivers/net/ethernet/realtek/r8169_main.c
+++ b/drivers/net/ethernet/realtek/r8169_main.c
@@ -5441,9 +5441,8 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 
 	netif_napi_add(dev, &tp->napi, rtl8169_poll, NAPI_POLL_WEIGHT);
 
-	dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO |
-		NETIF_F_RXCSUM | NETIF_F_HW_VLAN_CTAG_TX |
-		NETIF_F_HW_VLAN_CTAG_RX;
+	dev->hw_features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM |
+			   NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_CTAG_RX;
 	dev->vlan_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO |
 		NETIF_F_HIGHDMA;
 	dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
@@ -5460,26 +5459,26 @@ static int rtl_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
 		/* Disallow toggling */
 		dev->hw_features &= ~NETIF_F_HW_VLAN_CTAG_RX;
 
+	if (rtl_chip_supports_csum_v2(tp))
+		dev->hw_features |= NETIF_F_IPV6_CSUM;
+
+	dev->features |= dev->hw_features;
+
+	/* There has been a number of reports that using SG/TSO results in
+	 * tx timeouts. However for a lot of people SG/TSO works fine.
+	 * Therefore disable both features by default, but allow users to
+	 * enable them. Use at own risk!
+	 */
 	if (rtl_chip_supports_csum_v2(tp)) {
-		dev->hw_features |= NETIF_F_IPV6_CSUM | NETIF_F_TSO6;
+		dev->hw_features |= NETIF_F_SG | NETIF_F_TSO | NETIF_F_TSO6;
 		dev->gso_max_size = RTL_GSO_MAX_SIZE_V2;
 		dev->gso_max_segs = RTL_GSO_MAX_SEGS_V2;
 	} else {
+		dev->hw_features |= NETIF_F_SG | NETIF_F_TSO;
 		dev->gso_max_size = RTL_GSO_MAX_SIZE_V1;
 		dev->gso_max_segs = RTL_GSO_MAX_SEGS_V1;
 	}
 
-	/* RTL8168e-vl and one RTL8168c variant are known to have a
-	 * HW issue with TSO.
-	 */
-	if (tp->mac_version == RTL_GIGA_MAC_VER_34 ||
-	    tp->mac_version == RTL_GIGA_MAC_VER_22) {
-		dev->vlan_features &= ~(NETIF_F_ALL_TSO | NETIF_F_SG);
-		dev->hw_features &= ~(NETIF_F_ALL_TSO | NETIF_F_SG);
-	}
-
-	dev->features |= dev->hw_features;
-
 	dev->hw_features |= NETIF_F_RXALL;
 	dev->hw_features |= NETIF_F_RXFCS;
 
-- 
2.26.0

Re: [PATCH net 5.7] r8169: change back SG and TSO to be disabled by default

[David Miller]

From: Heiner Kallweit <hkallweit1@gmail.com>
Date: Sat, 4 Apr 2020 23:52:25 +0200

> There has been a number of reports that using SG/TSO on different chip
> versions results in tx timeouts. However for a lot of people SG/TSO
> works fine. Therefore disable both features by default, but allow users
> to enable them. Use at own risk!
> 
> Fixes: 93681cd7d94f ("r8169: enable HW csum and TSO")
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>

It's unfortunate we have to do this, but better safe than sorry.

Applied and queued up for -stable, and thanks for the backport.