Kernel
OF-nodes, Fwnodes, Swnodes, Devlinks, Properties - Understanding How Devices Are Modeled in Linux
<p>The linux kernel driver model has grown over the years and acquired several different mechanisms for passing device configuration data to platform drivers. This configuration can come from firmware (device-tree, ACPI) or from the kernel code itself (board-files, MFD, auxiliary drivers).</p>
<p>For a less experienced driver developer, the different APIs that are used to access device properties can be quite confusing and lead to questions: should I use the OF routines? Maybe fwnode or the generic device properties? What are software nodes in this model and what even is a device property? How are devices linked according to their provider-consumer relationship and their probe order ensured, if at all?</p>
<p>This talk will discuss the history and evolution of device properties - from legacy, custom platform data structures, through the introduction of the open-firmware API and its generalization to firmware nodes alongside other fwnode implementations up to the generic device property API. It will also touch on the devlinks and how they tie into this model.</p>
<p>The goal of this beginner/intermediate level talk is to give a clear picture of how device configuration should be handled in the kernel.</p>
Additional information
| Live Stream | https://live.fosdem.org/watch/ua2114 |
|---|---|
| Type | devroom |
| Language | English |
More sessions
| 2/1/26 |
<p>When a kernel component like a storage driver misbehaves in production, developers face a difficult choice. They either have too little information to solve the bug or they enable slow console-level debug logs that ruin performance. This talk introduces a per-component binary logging mechanism designed to support verbose logging in production with negligible run-time cost.</p> <p>We achieve this efficiency by moving the heavy lifting to build time. using preprocessor macros, we emit parameter ...
|
| 2/1/26 |
<p>For years, Ahmad’s ideal has been simple: unpack a rootfs on a server, mount it over NFS (or usb9pfs), boot directly into it, and everything just works™.</p> <p>But as secure boot becomes the default on many embedded systems, squeezing in a network-booted kernel is getting harder and often falls outside the supported boot flow entirely.</p> <p>Fortunately, some recent improvements in the kernel build system pave the way for a far less invasive netboot setup. This talk gives a quick tour ...
|
| 2/1/26 |
<p>A new RFC for Netfilter/nftables arrived recently in the netfilter-devel mailing list [1], introducing flexible math operation support for network packet fields. This could solve some migration problems from iptables to nftables and in addition empower other use-cases.</p> <p>This demo will quickly show how it works with simple real-world scenarios.</p> <p>[1] https://lore.kernel.org/netfilter-devel/20250923152452.3618-1-fmancera@suse.de/</p>
|
| 2/1/26 |
<p>Tracing complex systems often requires insights from both the kernel and userspace. While tools like Linux's ftrace excel at kernel-level observability and LTTng provides low-overhead userspace tracing, unifying these disparate data sources for a holistic view remains a challenge: using LTTng for kernel tracing requires an out-of-tree kernel module, which can be a barrier for many users.</p> <p>This talk introduces bt2-ftrace-to-ctf - a new open-source project designed to bridge this gap. Our ...
|
| 2/1/26 |
<p>Creating filesystem images typically requires mounting, copying files, and hoping your build environment doesn't introduce non-determinism. New capabilities in mkfs.xfs solve both problems. You can now populate an XFS filesystem directly from a directory tree at creation time, no mount required. I'll cover the implementation approach, discuss design, and show how to use it. Useful for distributions, embedded systems, and anyone who needs verifiable filesystem artifacts.</p> <p>Reference ...
|
| 2/1/26 |
<p>Correctness of operating system kernel code is very important. Testing is helpful, but does not always thoroughly uncover all issues. In the Whisper team at Inria, we are exploring the possibility of applying formal verification, using Frama-C, to Linux kernel code. This entails writing specifications, constructing loop invariants, and checking correctness with the support of a SMT solver. This talk will report on the opportunities and challenges encountered.</p>
|
| 2/1/26 |
<p>Most SoCs provide a PWM controller which it used mainly to drive LEDs, a display backlight or a fan. Less often a PWM controls a motor.</p> <p>The motor use case has a higher demand for exact control of the produced output. In the development cycle for Linux 6.13, the preferred abstraction for a PWM driver changed to be able to fulfill these needs.</p> <p>After a quick introduction about what a PWM actually does, Uwe (who is also the Linux PWM subsystem maintainer) will present the new API ...
|
