Скачать или смотреть Resolving the can-dev Module Loading Issue on Debian with Raspberry Pi

Discover how to effectively manage the `can-dev` module on Debian for a seamless experience with CAN bus on Raspberry Pi. This guide provides step-by-step solutions to the common issue of manual module reloading.
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This video is based on the question https://stackoverflow.com/q/70609980/ asked by the user 'Fux' ( https://stackoverflow.com/u/5334230/ ) and on the answer https://stackoverflow.com/a/70618436/ provided by the user 'Fux' ( https://stackoverflow.com/u/5334230/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Resolving the can-dev Module Loading Issue on Debian with Raspberry Pi: A Practical Guide

Using a CAN bus on a Raspberry Pi running Debian can sometimes present challenges, especially when certain modules do not load correctly at startup. One such problem encountered by many developers is the need to manually reload the can-dev module for it to function correctly even when it appears loaded. This guide will walk you through troubleshooting this issue and implementing a solution to ensure your CAN bus operates smoothly from the moment your Raspberry Pi starts up.

Understanding the Problem

After booting your Raspberry Pi and SSHing into it, the necessary kernel modules for the CAN bus should load automatically according to the configuration specified in /etc/modules-load.d/modules.conf. However, some users find that while the modules seem to be loaded, their CAN interfaces do not operate as expected until the can-dev module is manually reloaded.

Initial Setup

In the user's case, their /etc/modules-load.d/modules.conf included:

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After booting up, a quick check of the loaded modules with lsmod | grep can confirms that all relevant CAN modules, including can-dev, are listed. However, upon trying to communicate with devices through the CAN interface (can0), issues arise, and an unspecified error code is generated.

The Unexpected Dependency

Upon closer examination, it became apparent that the state of the can1 interface was influencing the performance of can0. Initially, can1 was down when the system started. It turns out that the can-dev module affected not only can0 but also can1. By manually reloading can-dev, the state of can1 changed to UP, enabling communication on can0:

Before reloading can-dev, the interface states were:

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After reloading, the states became:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

To ensure can1 is always up at startup, users can create an interface configuration file specifically for can1. This file will handle bringing can1 up automatically on boot, which addresses the issue without needing to manually reload can-dev each time.

Step-by-Step Instructions

Create Configuration File: Create a file named can1 in /etc/network/interfaces.d/.

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Add Configuration: Insert the following configuration into the file:

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Save and Exit: Save the changes and exit the text editor.

Reboot: Restart your Raspberry Pi to apply the changes.

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Final Thoughts

By creating a configuration for can1, you ensure that the CAN bus works seamlessly right from startup without the need for any additional commands. This guide illustrates how even a simple oversight can cause issues in system configurations and highlights the importance of thoroughly investigating seemingly minor elements as dependencies between modules.

If you find yourself still struggling with the setup or if you have insights regarding the necessity of reloading the module in the up part of the configuration, don't hesitate to share your thoughts with the community! Understanding these intricacies can greatly enhance not only your project but the collective knowledge as well.

Happy coding!