Before anything else: you need to know what hardware you have. This can be done by running a command called “lspci -v” which will show you all of the devices connected to your motherboard and their specifications. For example, let’s say we run this command on my laptop:
// This line shows the device's location and type, in this case a host bridge
01:00.0 Host bridge [0600]:
// This line shows the manufacturer and model of the device, in this case an Intel Xeon E3-1200 v5/E3-1500 v5/4th Gen Core Processor DRAM Controller
Intel Corporation Xeon E3-1200 v5/E3-1500 v5/4th Gen Core Processor DRAM Controller (rev 09) [8086:9d7a]
// This line shows the device's unique identifier, in this case the device's vendor ID and device ID
[8086:9d7a]
This tells us that we have an Intel processor with a specific revision number. Now, let’s say you want to enable support for your external card reader. To do this, you need to find the driver for it and add it to the kernel configuration file (which is called “.config” by default). This can be done using a text editor or by running commands in the terminal.
For example:
# Open the .config file with your favorite text editor
# Use sudo to run the command as root, allowing for necessary permissions
# Use the "nano" text editor to open the file
sudo nano /boot/config-$(uname -r)
# Add the following line to enable support for the external card reader driver (assuming it's called "sd_mod")
# This line adds the configuration for the external card reader driver to the kernel configuration file
CONFIG_SD_MOD=y
# Save and exit the file
# Use the keyboard shortcut "Ctrl + X" to exit the editor
# Press "Y" to confirm saving changes
# Press "Enter" to save the file with the same name
Ctrl + X, Y, Enter
Once you have made your changes, save the file and run a command like this to compile and install the new kernel:
# This script compiles and installs a new kernel using the make command.
# The -j$(nproc) flag allows for parallel compilation using all available processors.
# The && operator ensures that each command is executed only if the previous one was successful.
sudo make -j$(nproc) && # Compiles the kernel using all available processors.
sudo make modules_install && # Installs the kernel modules.
sudo make install # Installs the new kernel.
This will build the kernel with all of the selected options (including support for your external card reader), install it, and reboot your computer. And that’s it! You now have a custom-built kernel tailored to your specific hardware configuration.
Of course, this is just one example there are many other settings you can tweak depending on what you need. But the basic idea is always the same: know your hardware, make sane choices, and don’t be afraid to experiment!