LXQt Universal Wayland Session

A Wayland session for LXQt, managed by the Universal Wayland Session Manager (UWSM).

Motivation

The design of lxqt-session predates systemd and runs the entire session as child processes of a single parent process. This conflicts with systemd's recommendations and with how most other desktop environments are implemented.

By instead running each application in its own systemd user unit (as recommended by systemd), we avoid the risk that a single memory-hungry application will take down the entire session, and we gain the ability to easily inspect applications, e.g. with:

systemctl --user status <my-app>

Prerequisites

• LXQt
• UWSM

The following compositors are currently supported:

• Labwc (version 0.7.2 and higher)
• Miriway
• Wayfire
• KWin/Wayland
• Hyprland
• Niri
• river
• Sway

Installation

meson setup --prefix=/usr/local build
meson install -C build

Configuration

This repository does not provide compositor-specific configuration files. For LXQt-specific configuration for your compositor, see lxqt-wayland-session.

When configuring your compositor:

• Do not run lxqt-session, as UWSM replaces lxqt-session.
• Do not customize the environment in your compositor configuration, as UWSM provides its own environment-management facilities. Instead, place environment additions in ~/.config/uwsm/env-lxqt.
• Do not run lxqt-qdbus run, as UWSM provides its own uwsm app command for starting applications in the proper systemd slices.
• Do not autostart applications from your compositor configuration, as UWSM invokes systemd's standard autostart mechanism.

Usage

Log in to one of the LXQt (uwsm-managed) sessions in SDDM.

Implementation details

Upstream LXQt delivers its modules as XDG autostart desktop files with X-LXQt-Module=true, and lxqt-session treats these specially when starting the session. When running under UWSM, these autostart files are disabled and replaced with systemd services, which launch LXQt modules in the correct systemd slice and manage their lifecycle via systemd (including automatic restarts on failure).

Known issues

Applications launched from the LXQt panel or runner are not currently started in the correct systemd slice. As a short-term workaround, launch applications via:

• A compositor keybinding that runs uwsm app, or
• An alternative application runner that supports launch prefixes.

In the long term, LXQt itself should be enhanced to support launch prefixes as a first-class configuration option.

Future work

• Add OS packaging (pull requests welcome).
• Patch LXQt to support a launch prefix for uwsm app.
• Test more compositors and fix any remaining issues.