Re: [Intel-wired-lan] e1000e driver stuck at 10Mbps after reconnection

["Neftin, Sasha" <sasha.neftin@intel.com>]

On 8/7/2018 09:42, Camille Bordignon wrote:
> Le lundi 06 août 2018 à 15:45:29 (-0700), Alexander Duyck a écrit :
>> On Mon, Aug 6, 2018 at 4:59 AM, Camille Bordignon
>> <camille.bordignon@easymile.com> wrote:
>>> Hello,
>>>
>>> Recently we experienced some issues with intel NIC (I219-LM and I219-V).
>>> It seems that after a wire reconnection, auto-negotation "fails" and
>>> link speed drips to 10 Mbps.
>>>
>>>  From kernel logs:
>>> [17616.346150] e1000e: enp0s31f6 NIC Link is Down
>>> [17627.003322] e1000e: enp0s31f6 NIC Link is Up 10 Mbps Full Duplex, Flow Control: None
>>> [17627.003325] e1000e 0000:00:1f.6 enp0s31f6: 10/100 speed: disabling TSO
>>>
>>>
>>> $ethtool enp0s31f6
>>> Settings for enp0s31f6:
>>>          Supported ports: [ TP ]
>>>          Supported link modes:   10baseT/Half 10baseT/Full
>>>                                  100baseT/Half 100baseT/Full
>>>                                  1000baseT/Full
>>>          Supported pause frame use: No
>>>          Supports auto-negotiation: Yes
>>>          Supported FEC modes: Not reported
>>>          Advertised link modes:  10baseT/Half 10baseT/Full
>>>                                  100baseT/Half 100baseT/Full
>>>                                  1000baseT/Full
>>>          Advertised pause frame use: No
>>>          Advertised auto-negotiation: Yes
>>>          Advertised FEC modes: Not reported
>>>          Speed: 10Mb/s
>>>          Duplex: Full
>>>          Port: Twisted Pair
>>>          PHYAD: 1
>>>          Transceiver: internal
>>>          Auto-negotiation: on
>>>          MDI-X: on (auto)
>>>          Supports Wake-on: pumbg
>>>          Wake-on: g
>>>          Current message level: 0x00000007 (7)
>>>                                 drv probe link
>>>          Link detected: yes
>>>
>>>
>>> Notice that if disconnection last less than about 5 seconds,
>>> nothing wrong happens.
>>> And if after last failure, disconnection / connection occurs again and
>>> last less than 5 seconds, link speed is back to 1000 Mbps.
>>>
>>> [18075.350678] e1000e: enp0s31f6 NIC Link is Down
>>> [18078.716245] e1000e: enp0s31f6 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None
>>>
>>> The following patch seems to fix this issue.
>>> However I don't clearly understand why.
>>>
>>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> index 3ba0c90e7055..763c013960f1 100644
>>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>>> @@ -5069,7 +5069,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter)
>>>          case e1000_media_type_copper:
>>>                  if (hw->mac.get_link_status) {
>>>                          ret_val = hw->mac.ops.check_for_link(hw);
>>> -                       link_active = !hw->mac.get_link_status;
>>> +                       link_active = false;
>>>                  } else {
>>>                          link_active = true;
>>>                  }
>>>
>>> Maybe this is related to watchdog task.
>>>
>>> I've found out this fix by comparing with last commit that works fine :
>>> commit 0b76aae741abb9d16d2c0e67f8b1e766576f897d.
>>> However I don't know if this information is relevant.
>>>
>>> Thank you.
>>> Camille Bordignon
>>
>> What kernel were you testing this on? I know there have been a number
>> of changes over the past few months in this area and it would be
>> useful to know exactly what code base you started out with and what
>> the latest version of the kernel is you have tested.
>>
>> Looking over the code change the net effect of it should be to add a 2
>> second delay from the time the link has changed until you actually
>> check the speed/duplex configuration. It is possible we could be
>> seeing some sort of timing issue and adding the 2 second delay after
>> the link event is enough time for things to stabilize and detect the
>> link at 1000 instead of 10/100.
>>
>> - Alex
> 
> We've found out this issue using Fedora 27 (4.17.11-100.fc27.x86_64).
> 
> Then I've tested wth a more recent version of the driver v4.18-rc7 but
> behavior looks the same.
> 
> Thanks for you reply.
> 
> Camille Bordignon
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> 
I've agree with Alex. Let's try add 2s delay after a link event. Please, 
let us know if it will solve your problem.
Also, I would like recommend try work with different link partner and 
see if you see same problem.