Start by disabling one sound cart with bios
of removing one....
does kernels snd_ich doesn't work for you? (why you use oss from ports?)
I got ICH5 as well, and it works great...
Code:
pcm0: <Intel ICH5 (82801EB)> port 0xd800-0xd8ff,0xdc00-0xdc3f mem 0xf3101000-0xf31011ff,0xf3102000-0xf31020ff irq 17 at device 31.5 on pci0
magic part in kernel config
Code:
device sound
device snd_ich