mirror of
				https://github.com/Ysurac/openmptcprouter.git
				synced 2025-03-09 15:40:20 +00:00 
			
		
		
		
	
		
			
				
	
	
		
			61 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
			
		
		
	
	
			61 lines
		
	
	
	
		
			2.3 KiB
		
	
	
	
		
			Diff
		
	
	
	
	
	
From 5762758699e1ddab22bf4c14eb225941761c52c8 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 345/374] 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(-)
 | 
						|
 | 
						|
diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c
 | 
						|
index 28c47345420a..9eada927f572 100644
 | 
						|
--- a/drivers/net/usb/lan78xx.c
 | 
						|
+++ b/drivers/net/usb/lan78xx.c
 | 
						|
@@ -415,6 +415,15 @@ 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);
 | 
						|
@@ -2912,8 +2921,14 @@ static int lan78xx_bind(struct lan78xx_net *dev, struct usb_interface *intf)
 | 
						|
 	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;
 | 
						|
-- 
 | 
						|
2.16.1
 | 
						|
 |