The tg3 driver has had broken MTU handling since lk 2.4.21-pre5. After initially bringing the interface up with a MTU of 9000, or after changing the MTU setting, there is no RX activity until "ifconfig eth0 down; ifconfig eth0 up" is done. I reported this problem on the mailing list and to the maintainers more than a year ago and again a few months ago, only to be completely ignored. Maybe my message just didn't get through. Below is the patch to fix it. A better fix is probably possible, but I am not familiar with network driver programming. This is what happens without the patch: modprobe tg3 ifconfig eth0 192.168.1.2 netmask 255.255.255.0 mtu 1500 up ping 192.168.1.1 (ok) ifconfig eth0 mtu 9000 ping 192.168.1.1 (no response) ifconfig eth0 down ifconfig eth0 up ping 192.168.1.1 (ok) ifconfig eth0 down modprobe -r tg3 modprobe tg3 ifconfig eth0 192.168.1.2 netmask 255.255.255.0 mtu 9000 up ping 192.168.1.1 (no response) ifconfig eth0 down ifconfig eth0 up ping 192.168.1.1 (ok) ifconfig eth0 mtu 1500 ping 192.168.1.1 (no response) ifconfig eth0 down ifconfig eth0 up ping 192.168.1.1 (ok) This is what happens with the patch: modprobe tg3 ifconfig eth0 192.168.1.2 netmask 255.255.255.0 mtu 1500 up ping 192.168.1.1 (ok) ifconfig eth0 mtu 9000 ping 192.168.1.1 (ok) ifconfig eth0 down modprobe -r tg3 modprobe tg3 ifconfig eth0 192.168.1.2 netmask 255.255.255.0 mtu 9000 up ping 192.168.1.1 (ok) ifconfig eth0 mtu 1500 ping 192.168.1.1 (ok) The NIC I am using is a 3Com 3C996BT. Anthony J. Battersby Cybernetics diff -urN linux-2.4.27-vanilla/drivers/net/tg3.c linux-2.4.27-tg3/drivers/net/tg3.c --- linux-2.4.27-vanilla/drivers/net/tg3.c Sat Aug 7 19:26:05 2004 +++ linux-2.4.27-tg3/drivers/net/tg3.c Fri Aug 13 13:52:06 2004 @@ -3090,7 +3090,6 @@ return 0; } - tg3_netif_stop(tp); spin_lock_irq(&tp->lock); spin_lock(&tp->tx_lock); @@ -3102,7 +3101,6 @@ spin_unlock(&tp->tx_lock); spin_unlock_irq(&tp->lock); - tg3_netif_start(tp); return 0; } - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
