On Fri, 2009-04-24 at 09:33 -0400, Greg Wooledge wrote: > On Fri, Apr 24, 2009 at 12:29:23AM +0100, Ben Hutchings wrote: > > Do you also expect to get a gigabit link or only 100 megabit? > > The other end is set to 100/full. That is what I want to set the NIC to. > > > Please run "mii-tool -v eth0". > > img2:~# uptime > 08:37:59 up 1 min, 1 user, load average: 0.28, 0.12, 0.04 > img2:~# uname -a > Linux img2 2.6.26-2-686 #1 SMP Thu Mar 26 01:08:11 UTC 2009 i686 GNU/Linux > img2:~# mii-tool -v eth0 > eth0: no autonegotiation, 100baseTx-HD, link ok > product info: vendor 00:08:18, model 24 rev 0 > basic mode: autonegotiation enabled > basic status: autonegotiation complete, link ok > capabilities: 1000baseT-HD 1000baseT-FD 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD > advertising: 100baseTx-FD 100baseTx-HD 10baseT-FD 10baseT-HD flow-control > link partner: 100baseTx-HD As you can see, the other end only advertised 100BASE-T half-duplex, so that was the only possible result of autonegotiation. > > Is autonegotiation enabled at the other end of the link? > > No. The networking department here has a Policy of not using > autonegotiation, ever. My commiserations. Do they know that 1000BASE-T does not work without autonegotiation? [...] > I have been Googling intermittently for things like "Debian tg3 force > full duplex" for years and I have NEVER found a straight answer to > the relatively simple question of "How do you force a NIC to 100/full?" > > I am not explicitly setting autonegotiation. The driver module is > probably doing so when it's loaded by udev or discover or magical > leprechauns or whatever it is that Linux/Debian are using this year. Which is absolutely the correct default for a multi-speed NIC. [...] > So, now, the REALLY final test: > > img2:~# tail /etc/network/interfaces > > # The primary network interface > allow-hotplug eth0 > #iface eth0 inet dhcp > iface eth0 inet static > address 139.137.100.23 > netmask 255.255.255.0 > gateway 139.137.100.100 > up ethtool -s eth0 autoneg off speed 100 duplex full > # up sleep 5; mii-tool -F 100baseTx-FD eth0 This is the sensible approach now. In the current (unstable) package of ethtool I have added an ifupdown hook so these settings can be specified in interfaces without explicitly running ethtool. [...] > (Not that this will answer every question. I'm sure it will still fail > for lots of other people, because the correct answer seems to be something > along the lines of "It depends on which driver your NIC uses. You're > probably screwed. Try some other operating system and pray, or buy a > different NIC and pray, or both.") The ethtool command above should work for just about any Ethernet NIC under Linux, though obviously some drivers have bugs. Ben.
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