I have an IDE harddrive, which I thought I compiled in with menuconfig (gentoo 2007.0, latest kernel source) but when I boot I get a kernel panic saying that the root device /dev/sda4 cannot be found. I've tried enabling several option but can't get it right. Is there a way I can see what mount points use what modules? i.e. if in my live CD I mount /dev/sda4 to /mnt/gentoo can I see what module is used?

nevermind - fixed. I'd enabled PCI but not the intel IDE/PCI specific stuff.