ipconfig/dhcpcd don't work on self-compile kernel
 

I'm in the process of getting my gentoo up and running on my Averatec AV1020 lapstop. the networkcard is Realtek 8139 and wireless card is RaLink 2500. Well. I got the kernel compile w/ no error. But I have a problem after rebooted w/ the new kernel. The system recognize them as eth0 and ra0 no problem, but dhcpcd fail to find me any ip address, and neither setting ip manually by ifconfig will get me anywhere. I could config ip manually, but I still cannot ping any other machine or router w/in the same network. Pinging localhost is ok. I have compile quite a few kernel in the past for my other machine and giving me no problem, but not this one. If I boot from liveCD, it works fine also. Can someone point me to the good direction. And please don't tell me to change the distro. My conclusion so far is that:
1. pinging myself ok=ip stack work and ping work
2. LiveCD work=no hardware problem
3. eth0 and ra0 showup=driver recognize hardware
4. kernel problem, that's not linking hardware to software

So, what am I missing, tell me.

The network driver support, is it compiled in the kernel or with modules?
If so, did you check whether your network modules are loaded correctly?

my 8139too and rt2500 are built as modules, and they load w/o any error.

I finally figure it out, I need to pass the option "irqpoll" to the kernel when I boot. I'm not sure why, is it something I did when I compile my kernel to make it incompat, but yay it works now.