Fix: Xfreerdp Multimonitor Mirroring In CachyOS KDE Plasma

Hey guys! Ever run into that frustrating issue where your xfreerdp multimonitor setup mirrors the default desktop screen in fullscreen on CachyOS with KDE Plasma? Yeah, it's a pain, but don't worry, we're going to dive deep and figure out how to fix it. This comprehensive guide will walk you through the common causes, step-by-step solutions, and some advanced troubleshooting techniques to get your multimonitor setup working smoothly. Let's get started!

Understanding the Issue

When you're dealing with xfreerdp multimonitor problems, it's essential to first understand what's happening under the hood. The issue of the default desktop screen being mirrored in fullscreen typically arises from misconfigurations in how xfreerdp handles multiple monitors, especially within the KDE Plasma environment on CachyOS. To really nail this, let's break down the components and how they interact:

• xfreerdp: This is your Remote Desktop Protocol (RDP) client. It's responsible for connecting to the remote server and displaying the remote session on your local machine. When you specify multimonitor settings, xfreerdp needs to correctly map the remote displays to your local monitors.
• CachyOS: A Linux distribution known for its performance optimizations, CachyOS provides a robust base, but sometimes specific configurations are needed to ensure seamless multimonitor support with RDP clients.
• KDE Plasma: This is the desktop environment. Plasma is highly customizable, which is great, but it also means there are more settings that can potentially interfere with xfreerdp's multimonitor functionality. Plasma's display management settings play a crucial role in how monitors are detected and utilized.

At its core, the mirroring issue occurs when xfreerdp doesn't correctly interpret the monitor layout provided by KDE Plasma. This can result in the remote session being duplicated across all monitors instead of spanning them as intended. Identifying this miscommunication is the first step in resolving the problem. We need to ensure that xfreerdp receives the correct information about your monitor setup and can map the remote displays accordingly. Let's dive deeper into the potential causes. The common culprits include incorrect command-line arguments, misconfigured KDE Plasma display settings, and driver-related issues. By understanding these factors, you'll be better equipped to troubleshoot and implement the right solutions.

Common Causes for Mirroring Issues

Alright, let's get down to the nitty-gritty. The common causes for the xfreerdp multimonitor mirroring issue can be a mix of configuration quirks and compatibility hiccups. Identifying these will help you target the right solutions. So, what are the usual suspects?

1. Incorrect xfreerdp Command-Line Arguments

Your command-line arguments are the instructions you give to xfreerdp. If these aren't set up correctly, xfreerdp might not understand how to handle your multimonitor setup. Key arguments to watch out for include:

• /multimon: This is the big one! It tells xfreerdp to use all available monitors. If this is missing or not functioning correctly, you'll likely run into issues.
• /monitor-list: This allows you to specify which monitors to use. If you have a specific setup in mind (like using only two out of three monitors), this is crucial.
• /span: This option forces the remote session to span across all monitors, which can sometimes override other settings and cause unexpected behavior if not used correctly.
• /size: Manually setting the resolution can interfere with multimonitor setups if the specified size doesn't align with your monitor configuration.

2. Misconfigured KDE Plasma Display Settings

KDE Plasma is super flexible, but its display settings can sometimes conflict with xfreerdp. Key areas to check include:

• Monitor Arrangement: Make sure your monitors are arranged correctly in the Plasma display settings. If the virtual arrangement doesn't match your physical setup, xfreerdp can get confused.
• Primary Monitor: Ensure your primary monitor is correctly designated. Sometimes, xfreerdp relies on this setting to determine how to map the remote session.
• Scaling: Different scaling settings on different monitors can cause issues. Try setting all monitors to the same scaling factor to see if it resolves the mirroring.
• Resolution: Mismatched resolutions can also lead to problems. Ideally, your remote session's resolution should match the combined resolution of your monitors.

3. Driver-Related Issues

Your graphics drivers play a crucial role in how your system handles multiple monitors. Outdated or incompatible drivers can cause all sorts of display issues.

• Graphics Drivers: Make sure you're using the latest stable drivers for your graphics card. CachyOS, being a performance-focused distro, often benefits from the most up-to-date drivers.
• Driver Conflicts: Sometimes, having multiple graphics drivers installed (e.g., open-source and proprietary drivers) can lead to conflicts. Try using only one set of drivers to see if it makes a difference.

4. X Server Configuration

The X Server is the backbone of the graphical interface on Linux. Misconfigurations here can affect how xfreerdp interacts with your monitors.

• xorg.conf: Check your xorg.conf file (if you have one) for any manual monitor configurations that might be interfering with xfreerdp. In many modern setups, xorg.conf is automatically generated, but manual edits can sometimes cause issues.
• RandR (Resize and Rotate): This is an extension to the X Server that handles multimonitor setups. Make sure it's correctly configured and that xfreerdp is using it properly.

By carefully examining these potential causes, you're already halfway to fixing the problem. Now, let's move on to the solutions!

Step-by-Step Solutions

Okay, let's get into the real deal – fixing this mirroring madness! Here are some step-by-step solutions you can try to resolve the xfreerdp multimonitor issue on CachyOS with KDE Plasma. We'll start with the simplest solutions and move on to more advanced techniques.

1. Correcting xfreerdp Command-Line Arguments

First up, let's make sure your xfreerdp command is spot on. This is often the easiest fix, so it's a great place to start. Here’s what you should do:

1. Basic Multimonitor Command: Try the most straightforward approach first. Use the /multimon switch to tell xfreerdp to use all available monitors.

   xfreerdp3 /multimon /d:foobar.intranet /u:myuser /v:xx.xx.xx.31 +clipboard +sound -wallpaper /cert:ignore
   

2. Specify Monitor List: If /multimon doesn't work, or you want to use specific monitors, try the /monitor-list option. You'll need to identify your monitor IDs first. Use xrandr in your terminal to list your monitors and their IDs.

   xrandr | grep