Kernel/Configuration/Kernel Seeds

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Kernel seeds are pre-made kernel configuration files. They are not necessary to use when configuring a kernel, but they, along with tools such as genkernel, are helpful for users who may be unfamiliar with configuring the Linux kernel.

Concepts

Once upon a time a Gentoo user by the name of Pappy had an idea. Since configuring the Linux kernel can take much time out of a person's day, why not share generic configuration files with other users? Sharing a configuration file is as easy as putting a link to the file on the internet for any user to download. In Pappy's own words, Kernel Seeds are a "sane make defconfig for the real world."

What are the benefits of using Kernel Seed?

• Most default settings will be automatically configured.
• Time can be saved; using a pre-configured Seed is more efficient than starting without a .config file.

What are the hindrances of using Kernel Seeds?

• Negates learning the "tough stuff" for the user.
• In many cases users need to perform additional configuration steps in order to make the Seed bootable; seeds are not bootable "out-of-the-box".
• Usually the process (see below) takes longer than using Genkernel.

Configuration

Setting up the environment to use a Kernel Seed is not difficult at all, it's as simple a copying the .config file off the web into the current set of Kernel sources.

Verify the symlink is set to the newest emerged Kernel sources:

root #eselect kernel list

Substitute <number> in the next command with the desired Kernel sources number (left column) in the list printed by the previous command:

root #eselect kernel set <number>

Grab the Kernel Seed configuration file off the internet by using a utility of choice. wget (net-misc/wget) is used in the next example:

root #wget [Kernel-Seed-URL] -O /usr/src/linux/.config

Figure out what additional drivers the system will need by inspecting the PCI and USB devices with the appropriate tools. Installing sys-apps/pciutils and sys-apps/usbutils will be required for this step, as they contain the utilities for the task at hand.

root #lspci -nnk

root #lsusb -vv

View the output generated from lspci and lsusb. Add any needed drivers to the kernel configuration by using the menu target of choice (menuconfig, xconfig, gconfig):

root #make menuconfig

Once everything is set, run the the following make commands to built the new kernel:

root #make && make modules_install

Verify /boot is mounted (if applicable) and then install the newly build sources to the /boot location:

root #mount /boot

root #make install

If needed, perform additional steps to add the new kernel to the system's boot loader. Supposing the system uses GRUB2:

root #grub-mkconfig -o /boot/grub/grub.cfg

Reboot the system. After (if) the system reboots successfully look at the output of dmesg. A full log be can viewed by looking at the dmesg log file located at /var/log/dmesg with the pager of choice.

See also

• Genkernel — a tool created by Gentoo used to automate the build process of the kernel and initramfs.