First start machine with binary kernel that is prepared by gentoo. When the thing is running you should use modprobed-db to get info on modules that are running. Like this you kernel is configures only with what your machine support.
#
eselect kernel list
#
emerge --ask --verbose -b sys-kernel/modprobed-db
emerge --ask --verbose -b sys-kernel/gentoo-sources
#
modprobed-db store
#
cd /usr/src/linux
make LSMOD=$HOME/.config/modprobed.db localmodconfig
#
make -j $(nproc)
make modules_install
make installviola!