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From:   Stefano Cappa <stefano.cappa.ks89@gmail.com>
Date:   Thu, 27 Dec 2018 15:21:00 +0100
Message-ID: <CAKRytNzMHS-wN2_xSncf=a1Bgd=PVBV_GKHJw4tw1gc=_fkeNw@mail.gmail.com>
Subject: iMX6 FEC driver Linux-fslc 4.17 - IPV6 Multicast not working when
 unplugging/plugging ethernet cable
To:     fugang.duan@nxp.com, davem@davemloft.net, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
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Hi everyone,
I already posted this in NXP forum as a comment
(https://community.nxp.com/thread/359397), in yocto mailing list
(https://lists.yoctoproject.org/pipermail/yocto/2018-December/043664.html)
and in meta-freescale mailing list
(https://lists.yoctoproject.org/pipermail/meta-freescale/2018-December/023625.html)
A user in meta-freescale's mailing list suggested to resend this
message to the emails obtained running "./scripts/get_maintainer.pl -F
drivers/net/ethernet/freescale/fec_main.c".


The problem is:

If I boot my iMX6 device with ethernet cable attached and I execute "ping6
ff02::fb" to ping the multicast address I get this response:
~# ping6 ff02::fb
PING ff02::fb (ff02::fb): 56 data bytes
64 bytes from fe80::c2f:eff:fe11:2d71: seq=0 ttl=64 time=2.057 ms
64 bytes from fe80::809:1bfb:8d4c:ae54: seq=0 ttl=64 time=73.101 ms (DUP!)
64 bytes from fe80::3e28:6dff:feed:5b97: seq=0 ttl=64 time=150.772 ms
(DUP!)


Otherwise, If I unplug and plug again ethernet cable, I cannot ping the
multicast ipv6 address anymore.
The result is:
~# ping6 ff02::fb
PING ff02::fb (ff02::fb): 56 data bytes
ping6: sendto: Network is unreachable


The original NXP discussion was about older version of Linux, however
this issue is happening with both Linux 4.9.88 and Linux 4.17.
Probably also with the latest version, but I didn't try.


Do you have any suggestions? Is this a bug? This is really a
frustrating and I'm really
surprised to see the same problem also on Linux 4.17.


PS: I'm sorry for the double email, but the previous one was in html
and it was rejected.

Thank u.