My NIC uses the e100 driver. It would not properly autonegotiate with our switches in the office and always came up 100 Mbit half duplex. Based on reading the documentation, I added the following the /etc/modules.conf:

alias eth0 e100
options e100 e100_speed_duplex=4

This works great under kernel 2.4.x and I get 100 Mbit full duplex. However, I recently upgraded to 2.6.3 and dmesg shows that I am only getting half duplex again.

I verified that e100 is compiled as a module, and that the existing entries are still in modules.conf. I checked the driver documentation included in the kernel source and there don't appear to be any changes since the driver for 2.4.

Any ideas on how to get full duplex again with the e100 module?