** Description changed:
[ Impact ]
PipeWire 1.6.0 introduced a regression in the ALSA Sequencer bridge
- component (`spa.alsa.seq.bridge`), which handles port-naming conventions
+ component (spa.alsa.seq.bridge), which handles port-naming conventions
for all ALSA-based MIDI inputs and outputs. This regression breaks how
- these names are mapped into the JACK emulation layer (`pipewire-jack`).
+ these names are mapped into the JACK emulation layer (pipewire-jack).
In Ubuntu 26.04 LTS (which packages PipeWire 1.6.2), this directly
breaks port grouping in native JACK applications, patchbays, and session
managers like RaySession and Patchage. Instead of grouping all input and
output ports cleanly inside a single parent box representing a hardware
device or application, the ports fail metadata parsing and are presented
as a scattered mess of isolated "singleton" ports across the workspace
canvas. Furthermore, this completely breaks saved studio
scenes/projects, as RaySession can no longer properly resolve
connections based on the mangled port names.
The upload cherry-picks the upstream one-liner commit
(03fd89abeab5540251bede5015d0d85d76eaa71b) which corrects the client and
port naming string formatting inside the sequencer bridge. This ensures
legacy JACK string matching logic continues to work properly for client
applications.
[ Test Plan ]
This bug can be consistently reproduced on any machine without requiring
physical MIDI hardware by simulating virtual ALSA MIDI devices:
1. Install the required tools for testing the JACK abstraction layer:
$ sudo apt update && sudo apt install pipewire-jack jack-tools
2. Load the virtual MIDI kernel module to generate test streams:
$ sudo modprobe snd-virmidi
3. Check the exposed port-naming format in the JACK graph using the unpatched
PipeWire package:
$ pw-jack jack_lsp -p | grep -i "virmidi"
4. Observe the Buggy Behavior:
The output will expose malformed, multi-colon string mappings where the
client/port separation delimiters fail to match legacy standards
5. Install the updated/patched PipeWire package.
6. Fully restart the running user audio daemons to ensure the new binaries
are loaded into memory:
$ systemctl --user restart pipewire{,-pulse}{.service,.socket}
wireplumber.service
7. Run the test command again:
$ pw-jack jack_lsp -p | grep -i "virmidi"
8. Observe the Fixed Behavior:
The output strings will alter their formatting back to legacy-compliant,
properly delimited structures.
[ Where problems could occur ]
The upload changes string assignment behaviors for ALSA Sequencer MIDI
streams mapped to the PipeWire/JACK daemon ecosystem. If the patch were
wrong or incomplete, it could result in total failure to register MIDI
input/output ports entirely, meaning external keyboards or virtual MIDI
software would fail to show up in the connection graph.
Additionally, any niche or custom user script that was specifically
written during the lifecycle of PipeWire 1.6.0–1.6.2 and relied
explicitly on hardcoded matchings of the broken, malformed naming
convention strings might experience a breaking change when the strings
revert to their original, expected standards.
[ Other Info ]
The fix has already been merged and verified upstream, and it is
natively included in all newer versions of PipeWire starting from 1.6.3
up to the current upstream tags (e.g., 1.6.6). This backport simply
brings the Ubuntu 26.04 LTS package (stuck on 1.6.2) into parity with
the verified upstream stability fix.
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https://bugs.launchpad.net/bugs/2159565
Title:
[SRU] Fix port-naming formatting regression in ALSA sequencer bridge
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