From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: e100 + VLANs? Date: Sat, 08 Oct 2011 14:08:45 +0400 Message-ID: <4E90212D.8030009@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit To: netdev Return-path: Received: from isrv.corpit.ru ([86.62.121.231]:38107 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751575Ab1JHKIs (ORCPT ); Sat, 8 Oct 2011 06:08:48 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Yesterday I tried to use 802.1Q VLAN tagging with an (oldish) e100-driven network card, identified by lspci like this: 00:12.0 Ethernet controller: Intel Corporation 82557/8/9/0/1 Ethernet Pro 100 (rev 02) Just to discover that it does not quite work: packets of size 1497+ bytes gets lost. This appears to be a classical problems in this case - something forgot to allocate extra 4 bytes for the packets. There's at least one bugreport from 2008 (!) about this very issue: http://bugs.centos.org/view.php?id=2719 which is still open. 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. 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? 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 :) Thanks, /mjt