Update gentoo kernel

In gentoo, everything gets updated via portage using "emerge". For the kernel, emerge only updates the source. You have to manually configure, compile, and install the kernel source into a kernel binary. This is to allow you to keep your kernel tuned for your machine.

Gentoo installs the source here:

/usr/src/linux-#kernelversion#-gentoo-#gentooreleaseversion#

Because I have defined the "symlink" USE flag for gentoo-sources in /etc/portage/package.use, it will also symlink the latest downloaded source (whether you want it to or not) to:

/usr/src/linux

So once you emerge a new kernel source, you ought to install it or change the symlink if you don't have the time to do the kernel install.

Steps To Install Kernel

su -
emerge sys-kernel/gentoo-sources
cd /usr/src/linux
make menuconfig (and configure - see Configure MythTV kernel)
make && make modules_install
ls /boot
cp arch/x86_64/boot/bzImage /boot/kernel-genkernel-x86)64-#kernelversion#-gentoo-#gentooreleaseversion#_mdm-menuconfig
emacs /boot/grub/grub.conf (and add your shiny new kernel to the default top of the list)
reboot

Post-kernel-installation Steps

Since this involves video drivers, you probably have to do this outside X, so reboot and select a "softlevel=single" boot option.

install nvidia binary driver
install a new ivtv that matches the new kernel version

You should be able to use the following to automatically reinstall kernel-dependent modules:

module-rebuild rebuild

A more manual approach:

emerge nvidia-drivers
lsmod | grep nvidia && rmmod nvidia   # removes the previous module
modprobe nvidia                       # loads the new module

If you've done an emerge of media-video/nvidia-settings, you can run it to adjust the resolution, etc., dynamically in X.