linux-kernel - URGENT: ALSAfirewire Drivers Introduce 90ms delay

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Message-ID: <E7BF63E9-3CDF-4BD1-89BA-593215892369@gmx.de>
Date: Fri, 29 Aug 2025 11:33:33 +0200
From: "M. Armsby" <m.armsby@....de>
To: alsa-devel@...a-project.org, linux-kernel@...r.kernel.org
CC: tiwai@...e.de, Takashi Sakamoto <o-takashi@...amocchi.jp>
Subject: URGENT: ALSAfirewire Drivers Introduce 90ms delay - Linux is Unusable for Pro Audio

Dear maintainers,

Linux is being ridiculed in the professional audio community — not because it can't do low-latency audio, but because the ALSA FireWire stack  actively breaks it. Professional gear costing thousands of dollars like Motu RME Focusrite etc. etc. 

Since kernel 5.16+, FireWire audio devices are correctly detected and functional — but they are burdened with an artificial +90ms latency offset due to missing timing metadata (e.g., cycle-match delay, transmission latency) in the driver's interface to userspace.

PipeWire and WirePlumber rely on accurate latency reporting. When it's missing, they fall back to worst-case assumptions — adding ~90ms of delay. This is NOT a PipeWire bug. It is a FAILURE of the ALSA FireWire drivers to expose timing data that the hardware and firmware already provide.

This bug:
- Renders high-end interfaces (RME, Focusrite, Tascam, Motu, Terratec) unusable for real-time monitoring
- Forces users to hack WirePlumber with hardcoded quantum rules
- Damages Linux's credibility in music production
- Makes Linux a JOKE in studios worldwide

There is NO excuse for this in 2025.

We have workarounds (see: https://forum.cockos.com/showthread.php?t=274978), but they are fragile, device-specific, and do not scale.

We demand:
1. Immediate exposure of accurate device latency via ALSA control or hwdep interface
2. Proper reporting of transmission/cycle delay to userspace
3. A timeline for fixing this in mainline

This is not a "nice-to-have". It is a **critical defect** in a core multimedia subsystem now using pipewire as standard. 

Linux can and must do better.
Many are waiting to move to Linux, finally leaving windows. 

— Martin Armsby (Martin A - maa) 
Professional Audio Producer / Linux Advocate

Please see:
Imagine if Linux Audio just worked - Firewire  <https://forum.cockos.com/showthread.php?t=302305>
and
<https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/4785>
Thank you for reading.
-- Martin Armsby
-- Martin Armsby