Setserial Command on Linux with Examples

In the world of Linux, the setserial command is a powerful tool designed to set and/or report the configuration information associated with a serial port. This command is particularly useful for system administrators and developers who need to manage and troubleshoot serial devices on a Linux system. This article will provide a comprehensive guide on how to use the setserial command, including its installation, basic usage, advanced configurations, and best practices.

Understanding setserial

setserial is a program that allows users to set or report the configuration of a serial port. This includes information such as the I/O port and IRQ a particular serial port is using, and whether or not the break key should be interpreted as the Secure Attention Key, among other things. It’s important to note that for the most part, superuser privilege is required to set the configuration parameters of a serial port.

Installation of setserial

To install setserial, you can use the package manager of your Linux distribution. For Debian-based systems like Ubuntu, you would use:

sudo apt install setserial

For Red Hat-based systems like Fedora, you would use:

sudo dnf install setserial

For Arch Linux-based systems like Manjaro, you would use:

sudo pacman -S setserial

After installation, you can verify that setserial is installed and working correctly by typing setserial in the terminal. If the command is recognized, it means setserial is installed correctly.

Basic Usage of setserial

The basic syntax for the setserial command is:

setserial [options] device [parameter1 [arg]] ...

Here, device refers to the serial device you want to modify (e.g., /dev/ttyS0), and parameter1 [arg] refers to the parameters you want to set for the device.

 To display the current configuration of serial ports, use setserial -g:

# setserial -g /dev/ttyS*
/dev/ttyS0, UART: 16550A, Port: 0x03f8, IRQ: 4
/dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3

This checks /dev/ttyS0 and /dev/ttyS1. To query a single port, provide the device name:

# setserial /dev/ttyS1
/dev/ttyS1, UART: 16550A, Port: 0x02f8, IRQ: 3

Setting Parameters

To set parameters for a serial port, you can use the following syntax:

setserial /dev/ttyS0 irq 3

This command sets the IRQ for /dev/ttyS0 to 3. You can also set multiple parameters at once:

setserial /dev/ttyS0 port 0x02e8 irq 3 baud_base 115200

This sets the port, IRQ, and baud_base for /dev/ttyS0.

Advanced Configuration

setserial also allows for advanced configuration options, such as setting the UART type or configuring multiport cards. However, it is crucial to be cautious with these settings as incorrect configurations can cause system issues.

Troubleshooting

If you encounter issues with setserial, ensure that you have the correct permissions to modify serial port settings (usually root access is required). Also, verify that the parameters you are setting are correct for your hardware. Incorrect I/O port or IRQ settings can lead to system instability.

Conclusion

The setserial command is a powerful tool in Linux for managing and troubleshooting serial devices. By understanding its basic and advanced usage, system administrators and developers can effectively manage serial devices on a Linux system. As with any powerful tool, caution and best practices should be followed to ensure safe and effective use. With the knowledge provided in this article, you are now equipped to explore and utilize the setserial command in your Linux journey.