From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: e100 + VLANs? Date: Sat, 08 Oct 2011 18:24:06 +0200 Message-ID: <1318091046.5276.22.camel@edumazet-laptop> References: <4E90212D.8030009@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev To: Michael Tokarev Return-path: Received: from mail-ww0-f44.google.com ([74.125.82.44]:60482 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750742Ab1JHQYT (ORCPT ); Sat, 8 Oct 2011 12:24:19 -0400 Received: by wwf22 with SMTP id 22so7291940wwf.1 for ; Sat, 08 Oct 2011 09:24:18 -0700 (PDT) In-Reply-To: <4E90212D.8030009@msgid.tls.msk.ru> Sender: netdev-owner@vger.kernel.org List-ID: Le samedi 08 octobre 2011 =C3=A0 14:08 +0400, Michael Tokarev a =C3=A9c= rit : > Yesterday I tried to use 802.1Q VLAN tagging with an (oldish) > e100-driven network card, identified by lspci like this: >=20 > 00:12.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Etherne= t Pro 100 (rev 02) >=20 > Just to discover that it does not quite work: packets of > size 1497+ bytes gets lost. >=20 > This appears to be a classical problems in this case - > something forgot to allocate extra 4 bytes for the > packets. >=20 > There's at least one bugreport from 2008 (!) about this > very issue: http://bugs.centos.org/view.php?id=3D2719 > which is still open. >=20 > The kernel I tried this on was 2.6.32, I checked git log > for drivers/net/e100.c - there was no changes up to > current version which may be related to this issue. >=20 > The question: is this a driver problem or hardware? If > it's the driver, can it be fixed? And if it's hardware, > can the driver notify the user somehow - like, by refusing > to enable VLAN (sub)devices maybe? >=20 > Yesterday it was actually a bit more complicated for me, > since the card in question was used to connect to our > ISP, and they use fixed MAC address per port, so I had > to find another NIC which is a) able to work with VLAN > tags properly, and b) is able to change its mac address. > Lucky I had a VIA RhineIII which does both :) >=20 Since you have two cards (and probably two machines), maybe you could try to track if the problem is a bad transmit or a bad receive ? tcpdump on both machines, and ping -s 2000 from both sides... e100 driver seems VLAN enabled at a first glance.