LyDM discovers second monitor and changes resolution

Desktop Environments All WMs
1

I got a laptop with second monitor connected to it. I installed Hyprland on the base EndeavourOS installation. Ly as my DM. Works fine, logs me into Hyprland and both monitors work as expected.

However when Ly starts, when it asks me for my password, it discovers the second monitor and changes the resolution on my laptop and mirrors the display to the second monitor. The amount of columns, rows and font size changes on my main laptop display making it look weird.

Is there a way to force the system to discover the second monitor only after logging in through Ly?

2

I also use Ly with Hyprland. I doubt that Ly is responsible for this. You should be configuring your monitor setup in Hyprland. I used nwg-displays before switching to DankMaterialShell.

What do your Hyprland dotfiles show?

3

What part of hyprland dotfiles do you mean?

It`s a very basic configuration - pretty much files that hyprland ships with and a few changes in keybinds and monitor scaling:

monitor=eDP-2,preferred,auto,1.6

monitor=DP-5,preferred,auto,1

for startup i have this but i dont think it matters:

exec-once = hyprpolkitagent

exec-once = xdg-desktop-portal-hyprland

exec-once = waybar & hyprpaper

4

Yeah, agreed. The only thing I see wrong is the last exec-once line; should be:

exec-once = waybar &
exec-once = hyprpaper

I checked back to when I first installed Hyprland. My monitors config looked like this:

monitor=DP-1,1920x1080@143.99,0x0,1.0
monitor=DP-3,1920x1080@143.99,1920x0,1.0

I’ve always used Ly, so I’d try posting on the Hyprland Github/Forums pages.

5

The rest of these users (except @ajgringo619) are confusing Hyprland configuration for Ly configuration.

The short answer is no. Ly is a TUI (Text User Interface) display manager; it doesn’t have “monitor settings” because it runs directly in the Linux console (TTY). What you are seeing is the kernel’s Frame Buffer automatically detecting the second monitor and trying to “clone” the display at a compatible resolution for both screens.

Because Ly is just a frontend for the TTY, it has no power to “stop” the system from seeing a plugged-in monitor. To fix the “weird” resolution and font size, you have two options:

  1. Force Console Resolution: In your /etc/default/grub, set GRUB_GFXMODE=your_native_resolution (e.g., 1920x1080) and set GRUB_GFXPAYLOAD_LINUX=keep. This forces the kernel to stay at a specific resolution during the handoff to Ly, which usually prevents the “shifting columns” effect when a second monitor is detected.

  2. Kernel Boot Parameters: You can tell the kernel to ignore a specific video output until you’re logged in. For example, adding video=HDMI-A-1:d (where d is disable) to your boot line will “hide” that monitor from the TTY/Ly. However, you’d then need a line in your Hyprland config to explicitly re-enable it upon login.

Summary: Ly isn’t “discovering” your monitor—the kernel is. You have to handle this at the bootloader or kernel level, not within the display manager or compositor.

6

My bad, I am now realizing that it’s just the two of you in here. At glance it appeared someone was telling you to dig in your Hyprland configs, but I can see that was actually you bringing them up. Definitely not where you need to be looking. :slightly_smiling_face:

7

I figured it should have anything to do with Hyprland as it`s not being loaded at the time Ly is asking me for credentials. So i thought it has to be either at Ly or tty or even before.

I got systemd-boot instead of GRUB but i`ll try to find the settings to disable the second monitor.

Thanks!

8

No problem at all! Your intuition was spot on, and I’m glad I could help clear that up. I tried using Ly and Hyprland for quite a while so I know just enough to be dangerous. :slightly_smiling_face: