Dynamic Kernel Module Support (DKMS) is a framework that allows kernel modules to be dynamically built for each kernel on your system in a simplified and organized fashion.
In today’s tutorial, we’ll see how to use DKMS to build kernel modules in Nitrux.
Difficulty: ★★☆☆☆
📜 Table of Contents
Building DKMS modules in Nitrux
For this tutorial, we will build the Zenergy module. This kernel module is based on the AMD_ENERGY driver but with some jiffies added so non-root users can read it safely. The Zenergy kernel module is necessary for software like MangoHud to display the CPU power consumption for AMD Zen processors.
The DKMS source directory is typically located in /usr/src. Since this directory is in the root, we need to use overlayroot-chroot.
- ⚠️ Important: The commands below create, copy, edit, or move files in the root directory; see XFS Features and Root Immutability in Nitrux.
sudo overlayroot-chroot mount -t devtmpfs dev /dev git clone https://github.com/Nitrux/zenergy.git /usr/src/zenergy-1.0
We add the Zenergy module to DKMS by specifying the module name (zenergy) and version (1.0). This command registers the module with DKMS, preparing it for the build:
dkms add -m zenergy -v 1.0
With the module added, build it using DKMS. This compiles the module for the currently running kernel:
dkms build -m zenergy -v 1.0
Installing DKMS modules in Nitrux
Finally, install the module. The flag ensures the module installs even if previous versions or similar modules are installed:
dkms install --force -m zenergy -v 1.0
After these steps, your zenergy module should be built and installed successfully. We can exit the shell session using the following commands.
umount /dev sync exit
We must reboot to load the changes into the overlay.
Loading DKMS modules in Nitrux
Once the Zenergy module is installed, it must be loaded into the kernel for the system to use actively. Here’s how to manually load the module or set it to load automatically at boot.
To manually load the Zenergy module, use the following command:
modprobe zenergy
This command will insert the module into the running kernel. You can check if it loaded successfully with:
lsmod | grep zenergy
If the module is listed in the output, it is active in the kernel.
Alternatively, add it to the module loading configuration to ensure it loads automatically at each boot.
To ensure the Zenergy module loads automatically at each boot, add it to the module loading configuration.
- ⚠️ Important: The commands below create, copy, edit, or move files in the root directory; see XFS Features and Root Immutability in Nitrux.
Once again, we use overlayroot-chroot to add a file to the root directory.
- Create a configuration file in /etc/modules-load.d/:
echo "zenergy" | tee /etc/modules-load.d/zenergy.conf- 🔰 Information: This file tells the system to load the Zenergy module at boot.
- We must reboot to load the changes into the overlay.
After rebooting, confirm that the module is active by running:
lsmod | grep zenergy
If it appears in the list, the module will be successfully loaded on boot.
Troubleshooting
If you encounter issues during the DKMS module build or installation, you can use the following strategies to diagnose and resolve problems.
Common Limitations
- Kernel ABI Changes: DKMS might fail if the kernel ABI significantly changes. For better compatibility, it’s recommended that DKMS be used on a stable-release kernel.
- Initramfs Compatibility: DKMS modules will not load correctly if there are conflicts with modules in the initramfs.
Debugging Failed Builds
If the DKMS build fails, DKMS generates a make.log file, which logs the compilation steps and errors. You can view this log file to get more information about the issue. The log file is located in the following directory:
/var/lib/dkms/zenergy/1.0/build/make.log
Opening this file will provide detailed error messages and help identify the exact problem.
That’s it; this concludes today’s tutorial.