Fixing Hyprdynamicmonitors On Laptops Without AC Devices

Nov 2, 2025 by SLV Team 57 views

Hey guys! So, you're running into a snag with hyprdynamicmonitors on a laptop that doesn't seem to have the line_power_ACAD device? No worries, we've all been there. It's super frustrating when a config that works like a charm on one machine just throws a wrench in the works on another. This article will help you understand the problem and explore potential solutions so you can get hyprdynamicmonitors up and running smoothly on all your laptops. Let's dive in and get this sorted!

The Bug: Missing AC Power Device Blues

Alright, let's break down the issue. You've got this awesome service, hyprdynamicmonitors, set up, and it's doing its magic, handling multiple monitor setups and adjusting profiles based on whether you're on AC power or battery. Awesome, right? But then, you try to deploy this same setup to an older laptop, and BAM! It fails. Why? Because the older laptop's upower devices look a little different. Instead of the expected line_power_ACAD, you might only see line_power_ADP0 or even just the battery and display devices. This difference in hardware configurations causes the service to stumble because it's looking for a specific device that isn't there.

This is a classic case of a configuration designed for a particular hardware setup not being universally compatible. The problem isn't necessarily that the service is fundamentally broken; it's that it's too specific in its expectations. It's like having a key that only fits one lock. When you try to use it on a different lock, it just won't work. The goal is to make the service more adaptable so it can work with different hardware configurations without needing a complete overhaul. That's the essence of what we're trying to achieve here!

The core of the problem lies in the upower device detection. The service is likely checking for the existence of line_power_ACAD and, if it doesn't find it, it's either crashing or not enabling the power-related features. In the context of your older laptop, this check fails, and the service behaves in an unexpected way. This situation is particularly annoying because you probably don't even need the power features on the older laptop. You just want the service to run without crashing and to handle the monitor configuration as intended.

The solution? We need to make hyprdynamicmonitors more flexible in its handling of upower devices. It needs to gracefully handle the absence of line_power_ACAD and potentially adapt its behavior accordingly. For instance, if line_power_ACAD isn't present, the service could simply disable the power-related features and continue functioning based on other criteria, such as the battery status or a default configuration. This kind of adaptability is crucial for creating a robust and user-friendly experience across a variety of hardware setups.

To summarize, the bug is a result of the service being too specific in its expectations of the upower devices present on the system. The service is unable to adapt when the line_power_ACAD device is not present. This is causing the service to fail on older laptops that have different upower devices.

Reproducing the Issue: The Steps

To fully understand the bug, let's look at how to reproduce it. The steps are pretty straightforward. You're using a Nix configuration, which is fantastic for reproducibility. Here's a breakdown:

Service Setup: You've configured the hyprdynamicmonitors service using a Nix configuration. This is key because it means the setup is declarative and should be consistent across machines. The configuration you're using is defined in a specific file. This file likely contains the logic that determines how hyprdynamicmonitors behaves and interacts with the upower devices.
Configuration: You're using a specific configuration file. This file likely contains the logic that determines how hyprdynamicmonitors behaves and interacts with the upower devices. This is where the service detects the presence of line_power_ACAD and potentially enables or disables power-related features.
Older Laptop: You deploy this configuration to an older laptop. This is where the issue surfaces because the older laptop has a different set of upower devices. The critical difference is the absence of line_power_ACAD.
Service Failure: Because the line_power_ACAD device is missing, the service fails to operate as expected. It might crash, fail to enable power-related features, or simply not function correctly. This is the observable manifestation of the bug.

So, by following these steps, you can reliably reproduce the bug. This is incredibly important for diagnosing and fixing the problem because it means you can consistently recreate the conditions that lead to the failure. This helps you test potential fixes, ensuring that they work and don't introduce new issues. Having a clear set of reproduction steps is the cornerstone of effective bug fixing.

The reproduction steps highlight the importance of the difference in hardware configurations. They underscore the need for the service to be adaptable to a variety of hardware setups, rather than assuming a specific configuration. The reproduction steps also point to a specific area of the configuration that is failing, which helps to narrow down the areas of code that need modification.

Expected Behavior vs. Reality

The expected behavior is simple: the service should work. Even if the power features aren't enabled on the older laptop (which you don't even need), the service should still function, especially in terms of handling monitor configurations. It's like, the bare minimum, right?

However, the reality is different. Because of the missing line_power_ACAD device, the service fails. This means the service might:

Crash: The service completely stops working due to an error during startup or operation.
Fail to Enable Power Features: The service detects the absence of line_power_ACAD and, as a consequence, refuses to enable power-related features, such as adjusting screen brightness based on AC/battery status.
Misbehave: The service operates in an unpredictable manner, potentially leading to incorrect monitor configurations or other issues.

This discrepancy between expected and actual behavior points to a crucial flaw in the service's design. The service is not gracefully handling the absence of a specific hardware device. Instead of adapting, it's simply breaking. This is a common issue in software development, and the fix usually involves adding error handling and adaptability.

To improve the service, it needs to be more resilient to variations in hardware configurations. It should be able to:

Detect Missing Devices: The service should check for the presence of the required devices, such as line_power_ACAD.
Handle Missing Devices Gracefully: If a device is missing, the service should not crash or fail. Instead, it should log a warning and either disable the corresponding features or use alternative strategies.
Adapt its Behavior: The service should adapt its behavior based on the available hardware. For example, if line_power_ACAD is missing, the service could default to battery status or a fixed configuration.

The goal is to create a more robust and user-friendly experience by allowing the service to function correctly, even when the underlying hardware differs. This ensures that the user's experience is consistent across all machines.

The Technical Details: Diving Deeper

Let's get into some technical specifics. The core of the problem, as you've identified, revolves around the upower devices and how hyprdynamicmonitors interacts with them. Understanding these details will help us develop solutions.

upower: This is the tool that provides information about power devices, like batteries, AC adapters, and more. It exposes this information through a D-Bus interface. Your service uses this information to determine the power source (AC or battery) and make decisions based on that.
line_power_ACAD: This specific device represents the AC power source. Its presence or absence is a critical factor in your setup because it's used to trigger specific behaviors. The service is likely configured to look for this device and, if it's present, enable certain power-related features.
D-Bus Interface: upower uses D-Bus to communicate with other services. hyprdynamicmonitors likely uses D-Bus to query upower for information about the power devices. This is how the service gathers the information about whether the laptop is on AC power or running on battery.
Nix Configuration: This is how you manage your system's configuration. It's a declarative way to specify what software is installed and how it's configured. Your service's configuration is defined in a Nix file, which determines how hyprdynamicmonitors interacts with upower and other system components.

So, the service's logic probably does something like this:

Query upower: The service queries upower via D-Bus to get a list of available devices.
Check for line_power_ACAD: The service checks if line_power_ACAD is present in the list of devices.
Enable Power Features (if present): If line_power_ACAD is present, the service enables power-related features, such as setting screen brightness or adjusting monitor configurations.
Failure (if absent): If line_power_ACAD is missing, the service either crashes or fails to enable power-related features, leading to the problem you're experiencing.

To fix the issue, you'll need to modify this process to handle the case where line_power_ACAD is missing. This could involve checking for other AC power devices (like line_power_ADP0), using the battery status as a fallback, or simply disabling the power-related features altogether.

Possible Solutions: Making it Work

Now, let's explore some potential solutions to get hyprdynamicmonitors working smoothly on your older laptop. We'll focus on making the service more adaptable to different hardware configurations.

Conditional Logic: The most straightforward solution is to add conditional logic to your configuration file. This means checking for the presence of line_power_ACAD (or other AC power devices) before attempting to enable the power features. If the device isn't present, the service could:
- Disable the power features.
- Use a default configuration.
- Check for alternative AC power devices.
- Log a warning message indicating that the power features are unavailable.
This approach involves modifying the Nix configuration file to include an if statement or a similar construct that checks for the presence of the device. This provides flexibility and allows you to tailor the service's behavior to the specific hardware configuration.
Fallback Mechanism: If line_power_ACAD is missing, you could implement a fallback mechanism. This could involve using the battery status (e.g., if the battery is charging, assume AC power) or using a default configuration. The fallback mechanism should be designed to ensure that the service functions correctly even when the primary power detection method fails.
Device Agnostic Approach: Instead of relying on specific device names, you could modify the service to determine if it is on AC power based on the state of the line power devices. The key is to find a reliable way to determine if the laptop is connected to AC power without relying on a specific device name. This could involve checking the state of a device like line_power_ADP0 or analyzing the battery charging status. The goal is to make the service more resilient to hardware variations.
Configuration Options: Add configuration options to the service. This would allow you to specify how the service should behave when the line_power_ACAD device is missing. You could provide options like:
- use_ac_detection: (true/false) - Enables or disables AC power detection.
- default_profile: (string) - The profile to use if AC power detection fails.
This would give you more control over the service's behavior and make it easier to adapt to different hardware configurations. The advantage is increased flexibility and customization for each user.
Community Contributions: If you're not comfortable modifying the configuration yourself, consider reaching out to the project maintainers. Explain the issue and suggest potential solutions. You could even offer to help test the changes. Open-source projects thrive on community contributions, and your input could significantly improve the service.

Implementation: Code Examples

Let's get into some practical code examples. Remember, these are illustrative and you'll need to adapt them to your specific Nix configuration. We'll focus on the conditional logic approach, as it's the most direct way to solve the problem.

# Hypothetical Nix configuration snippet
let
  upowerDevices = lib.lists.map (dev: toString dev) (builtins.readDir /sys/class/power_supply);
  hasAcDevice = lib.any (dev: builtins.stringLength (lib.string.match "line_power_ACAD" dev) > 0) upowerDevices;
 in
 {
   services.hyprdynamicmonitors = {
     enable = true;
     # ... other configurations ...
     settings = {
       # ... other settings ...
       ${if hasAcDevice then "acSettings" else "defaultSettings"} = {
         # Settings for AC power
         brightness = 100;
         monitorConfig = {
           # AC power monitor config
         };
       };
       defaultSettings = {
         # Settings for battery power or no AC
         brightness = 50;
         monitorConfig = {
           # Default monitor config
         };
       };
     };
   };
 }

In this example:

upowerDevices: A list of the found devices.
hasAcDevice: A boolean value that is true if the device is found.
The code then checks if hasAcDevice is true. If it is, it uses the acSettings; otherwise, it uses defaultSettings.

This simple example shows how you can adapt the behavior of hyprdynamicmonitors based on the presence of the line_power_ACAD device. You can extend this logic to handle other scenarios, such as checking for alternative AC power devices or using a fallback mechanism.

Remember to test your changes thoroughly to ensure they work as expected and don't introduce any new issues.

Testing and Validation: Making Sure it Works

Testing is a crucial part of the process. You need to confirm that your changes have the intended effect and don't break anything else. Here's how you can approach testing:

Reproduce the Bug: Start by reproducing the original bug on your older laptop. This ensures you have a baseline to compare against.
Implement Your Solution: Make the changes to your Nix configuration. This might involve adding conditional logic, implementing a fallback mechanism, or adjusting the service's configuration.
Deploy the Changes: Deploy your updated configuration to both your older and newer laptops. This ensures that the changes work as expected on both hardware configurations.
Verify the Behavior: Carefully observe the behavior of hyprdynamicmonitors on both laptops.
- Older Laptop: Verify that the service no longer crashes or fails. Check that monitor configurations are applied correctly, and that the service functions as expected, even without the power features.
- Newer Laptop: Verify that the service continues to function as before. Ensure that the power features work as expected and that the monitor configurations are applied correctly.
Log Analysis: Check the service's logs for any errors or warnings. This can provide valuable insights into what's happening under the hood.
Edge Cases: Test edge cases. For instance, what happens if you plug in the AC adapter on your older laptop after the service has started? How does the service respond? This will help you validate the robustness of your solution.
Version Control: Commit your changes to version control (e.g., Git) after each successful test. This allows you to track your progress, revert to previous versions if necessary, and easily share your changes with others.

Testing is an iterative process. You might need to make several adjustments before you achieve the desired results. Don't get discouraged! This is a normal part of software development. Every test result, whether positive or negative, gives you valuable information. By following these steps, you can confidently address the issue and ensure that hyprdynamicmonitors works seamlessly across all your laptops.

Conclusion: Keeping it Running

There you have it, guys! We've walked through the problem of hyprdynamicmonitors failing on laptops that lack the line_power_ACAD device. We've talked about the bug, how to reproduce it, and various solutions, from adding conditional logic to implementing fallback mechanisms. Remember, the goal is to make the service as flexible as possible so it works well on different hardware configurations.

By following these steps and adapting the code examples, you should be able to get your service running smoothly on all your laptops. Remember to test thoroughly and iterate on your solution until you're happy with the results. This is a journey of continuous improvement, and your contributions and willingness to learn and adapt are essential. This will improve not just your setup but also the experience for other users. Now go forth and make those monitors dynamic!