linux-kernel - Re: [BUG] igb: reconnecting of cable not always detected

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Date:   Thu, 26 Apr 2018 09:54:27 +0200
From:   Holger Schurig <holgerschurig@...il.com>
To:     Alexander Duyck <alexander.duyck@...il.com>
Cc:     Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        intel-wired-lan <intel-wired-lan@...ts.osuosl.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [BUG] igb: reconnecting of cable not always detected

> Was the orange LED on the igb NIC or on the TL SG-108? Based on the
> comment below I am assuming it is the switch.

The LEDs were on the switch.

When everything works, the switch says green == 1000 MB/s.

When cable is disconnected, switch doesn't light any LED.

When cable is inserted and things fail, the switch says orange LED == 100 MB/s.
Sometimes the insertion process works, then the switch will go, of
course, to the green LED == 1000 MB/s.

I must admit that I didn't look at the LEDs of the device.


Now I looked there, and the device the left+green LED is on. In the
failed case (so, in the dmesg output the last thing I see is "Link is
Down", but the device still has left+green LED on.

The right+orange LED on the device seems to indicate traffic, and it is
constantly off in the failed case.



> I assume you mean "ethtool -r" since that is what is supposed to be
> restarting negotiation. The "ethtool -i" is what you provided above.

Maybe I've edited my text too much and moved output along. Anyway, in
the failed case neither "ethtool- r eth0" nor "ethtool -i eth0" nor
"mii-tool eth0" work at all, they all emit error warning.

> Thanks. I'm suspecting we may need to instrument igb_rd32 at this
> point. In order to trigger what you are seeing I am assuming the
> device has been detached due to a read failure of some sort.

I'll do that and reply later. I first need to understand this source
part :-)


> Another thing you could look at doing is narrowing down the possible
> factors involved. You could go through and limit phy settings and look
> at possibly dropping features such as EEE if it is enabled on the
> device.

I actually tried a driver patch to remove 1000 GB/s from the driver, in
the assumption that maybe this specific hardware has a bad layout and
thus trouble (I don't really think that, because I never observed any
data transfer problem).

So, is the following patch (that didn't help) what in the line of what
you suggested?


Index: linux-4.16/drivers/net/ethernet/intel/igb/igb_main.c
===================================================================
--- linux-4.16.orig/drivers/net/ethernet/intel/igb/igb_main.c	2018-04-01 23:20:27.000000000 +0200
+++ linux-4.16/drivers/net/ethernet/intel/igb/igb_main.c	2018-04-24 11:35:17.420760650 +0200
@@ -2080,7 +2080,7 @@
 
 	if ((adapter->flags & IGB_FLAG_EEE) &&
 	    (!hw->dev_spec._82575.eee_disable))
-		adapter->eee_advert = MDIO_EEE_100TX | MDIO_EEE_1000T;
+		adapter->eee_advert = MDIO_EEE_100TX /* | MDIO_EEE_1000T */;
 
 	return 0;
 }
@@ -2908,7 +2908,7 @@
 	/* Initialize link properties that are user-changeable */
 	adapter->fc_autoneg = true;
 	hw->mac.autoneg = true;
-	hw->phy.autoneg_advertised = 0x2f;
+	hw->phy.autoneg_advertised = 0x0f;
 
 	hw->fc.requested_mode = e1000_fc_default;
 	hw->fc.current_mode = e1000_fc_default;
@@ -3099,7 +3099,7 @@
 			if ((!err) &&
 			    (!hw->dev_spec._82575.eee_disable)) {
 				adapter->eee_advert =
-					MDIO_EEE_100TX | MDIO_EEE_1000T;
+					MDIO_EEE_100TX /* | MDIO_EEE_1000T */;
 				adapter->flags |= IGB_FLAG_EEE;
 			}
 			break;
@@ -3110,7 +3110,7 @@
 				if ((!err) &&
 					(!hw->dev_spec._82575.eee_disable)) {
 					adapter->eee_advert =
-					   MDIO_EEE_100TX | MDIO_EEE_1000T;
+					   MDIO_EEE_100TX /* | MDIO_EEE_1000T */;
 					adapter->flags |= IGB_FLAG_EEE;
 				}
 			}
Index: linux-4.16/drivers/net/ethernet/intel/igb/igb_ethtool.c
===================================================================
--- linux-4.16.orig/drivers/net/ethernet/intel/igb/igb_ethtool.c	2018-04-01 23:20:27.000000000 +0200
+++ linux-4.16/drivers/net/ethernet/intel/igb/igb_ethtool.c	2018-04-24 11:42:36.737959749 +0200
@@ -170,7 +170,7 @@
 			     SUPPORTED_10baseT_Full |
 			     SUPPORTED_100baseT_Half |
 			     SUPPORTED_100baseT_Full |
-			     SUPPORTED_1000baseT_Full|
+			     /* SUPPORTED_1000baseT_Full| */ 
 			     SUPPORTED_Autoneg |
 			     SUPPORTED_TP |
 			     SUPPORTED_Pause);
@@ -3003,7 +3003,7 @@
 	    (hw->phy.media_type != e1000_media_type_copper))
 		return -EOPNOTSUPP;
 
-	edata->supported = (SUPPORTED_1000baseT_Full |
+	edata->supported = (/* SUPPORTED_1000baseT_Full | */
 			    SUPPORTED_100baseT_Full);
 	if (!hw->dev_spec._82575.eee_disable)
 		edata->advertised =