From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: 2.4.21: bug report for tg3: tx lockup when changing MTU Date: Fri, 01 Aug 2003 17:24:00 -0700 Sender: netdev-bounce@oss.sgi.com Message-ID: <3F2B04A0.9030101@candelatech.com> References: <3F2AEFBF.3040604@candelatech.com> <3F2AFE7A.10203@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: "'netdev@oss.sgi.com'" Return-path: To: Jeff Garzik In-Reply-To: <3F2AFE7A.10203@pobox.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Jeff Garzik wrote: > Ben Greear wrote: > >> I just noticed that if you change the MTU of a tg3 NIC, it will not work >> untill you ifdown/ifup it. This problem is repeatable on tg3, and >> does not >> happen with the e1000 driver/cards. >> >> I am setting the MTU via an ioctl call, not via ifconfig or something >> like >> that. > > > > Can you provide the ioctl call info, so I can reproduce? > > And, are you changing MTU when the interface is up or down? Interface is up and transmitting/receiving pkts at the time. I just reproduced it with commands below. It is probably a race, so not sure that either of these will always fail. Running about 10kpps rx+tx. Was sending pktgen (UDP) traffic of fixed length, so the actual transmitted packet sizes remains the same in this case. # MTU is at 1500 ifconfig eth5 mtu 4096 #worked ifconfig eth5 mtu 4000 # failed. -- Ben Greear Candela Technologies Inc http://www.candelatech.com