fix(asusd-user): wait dynamically for system daemon on D-Bus

[scardracs]

Problem & Symptoms

On several ASUS ROG laptop models (e.g., Strix SCAR 16 G635LW) using version 6.3.9, special hotkeys (Volume Up/Down, Mic Mute, Fan profile speed toggle, ROG Key) ceased working after system boot.

Root Cause

In version 6.3.9, the system daemon (asusd) performs several complex/asynchronous initialization tasks on startup (such as default fan curve ACPI queries, XG Mobile LED checks, and D-Bus firmware attribute registration), which noticeably prolonged its overall boot sequence. The user-level daemon (asusd-user) was configured to start blindly after a 2-second sleep (ExecStartPre=/usr/bin/sleep 2 in the systemd user service). Because asusd took longer than 2 seconds to register its name (xyz.ljones.Asusd) on D-Bus:

1. asusd-user failed to query the available D-Bus interfaces and crashed on start.
2. Under systemd's default restart policies (StartLimitBurst=2 in 200 seconds), asusd-user exhausted its startup attempts after two failures and was permanently disabled for the rest of the boot session, breaking all special hotkeys.
   Furthermore, keeping StartLimitBurst=2 meant that if the system daemon was restarted manually a couple of times during a session, the user daemon would crash (due to D-Bus disconnection) and quickly hit the restart limits, leaving the service disabled permanently until manually restarted.

Proposed Changes

This PR resolves the startup race condition and improves the overall robustness of the user service:

1. Dynamic D-Bus Wait in asusd-user (Commit 1):

   • Replaced the immediate startup crash in list_iface_blocking() at boot with a deterministic check of the D-Bus name owner status.
   • If xyz.ljones.Asusd has no owner yet, the daemon subscribes to the D-Bus system daemon's NameOwnerChanged signal and blocks dynamically.
   • Once asusd registers its name and becomes ready, asusd-user breaks the loop and continues its initialization. This is fully event-driven and resource-friendly.

2. Systemd Service Clean Up & Restart Limits Removal (Commit 2):

   • Removed the obsolete ExecStartPre=/usr/bin/sleep 2 from data/asusd-user.service, enabling the service to spawn instantly and wait cleanly in code.
   • Removed the aggressive StartLimitInterval=200 and StartLimitBurst=2 options, delegating rate-limiting of restarts to standard systemd defaults (e.g., 5 restarts in 10 seconds), preventing the daemon from getting stuck in an inactive state.

Commits

• fix(asusd-user): wait dynamically for system daemon on D-Bus — Updates asusd-user/src/daemon.rs with the dynamic wait logic.
• fix(systemd): clean up user service startup and restart limits — Updates data/asusd-user.service to remove the sleep workaround and the start limit constraints.

[Ghoul4500]

Is there any reason why we can't simply do something like

[Unit]
After=asusd.service
Wants=asusd.service

if we are doing any waiting though, adding timeout is also important

[scardracs]

Is there any reason why we can't simply do something like

[Unit]
After=asusd.service
Wants=asusd.service

if we are doing any waiting though, adding timeout is also important

A user-level systemd instance cannot see or wait for system-level services directly in After=. A user service can only see other user services.

[Copilot]

Pull request overview

This PR fixes a startup race between asusd-user and the system daemon (asusd) by replacing a fixed systemd sleep with an event-driven wait for xyz.ljones.Asusd to appear on the system bus, improving hotkey reliability after boot and across daemon restarts.

Changes:

• Removed the systemd ExecStartPre=/usr/bin/sleep 2 workaround and the custom StartLimit* settings from the user unit.
• Added a blocking wait in asusd-user for the xyz.ljones.Asusd D-Bus name owner to appear (with a 30s timeout), then proceeds to interface discovery.
• Switched some stdout prints to structured logging and added the log dependency.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
data/asusd-user.service	Removes fixed sleep and restart limit overrides so startup ordering is handled in-code.
asusd-user/src/error.rs	Adds a dedicated timeout error for the new D-Bus wait path.
asusd-user/src/daemon.rs	Implements D-Bus name-owner wait before querying interfaces; changes startup output to log macros.
asusd-user/src/ctrl_anime.rs	Replaces a println! error path with log::error!.
asusd-user/Cargo.toml	Adds log as a workspace dependency for the new logging usage.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Ghoul4500]

this last change fr