Public bug reported:
/home/flavio/audio_hdmi/informe_bug.md
/home/flavio/audio_hdmi/testar.sh
/home/flavio/audio_hdmi/tono440.wav
/home/flavio/audio_hdmi/tono441.wav
- Problem: HDMI audio cuts out constantly (robotic sound), while the analog
output on the same machine—using the same stream—sounds perfect. Furthermore,
the same cable/port provides clear audio in Windows, ruling out both the cable
and the monitor.
- Reproduction: Running `pw-play --target
alsa_output.pci-0000_00_03.0.hdmi-stereo tono441.wav` shows the `trigger_time`
changing 8–10 times per second (cycling through RUNNING → XRUN → SETUP); using
`aplay` directly results in an `EIO` error on the first write.
- Key log entry: `spa.alsa: hdmi:1p: snd_pcm_avail after recover: EPIPE (Broken
pipe)`
- Measurements: `hw_params` sets a buffer of 32,768 samples, but the pointer
bounces back at ~8,192, regressing ~15 times over 2 seconds (e.g., 8232 → 48).
This results in 126 anomalies per second, which aligns with the 860 `ERR` count
reported by `pw-top`. The analog driver, by contrast, shows 0 anomalies.
- Environment: Ubuntu 26.04.1, kernel 7.0.0-38.38, X240 with BIOS GIET99WW,
8086:0a0c Haswell HDMI, PipeWire 1.6.2-1ubuntu1.2; ELD is stable, PCI power
management is ruled out (`runtime_suspend_time=0`), and the issue is unrelated
to resampling.
- Workarounds tested: Setting `quantum` to 4096 (no change); `power_save=0`
(already applied).
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: flavio 6833 F.... wireplumber
/dev/snd/controlC0: flavio 6833 F.... wireplumber
/dev/snd/seq: flavio 6824 F.... pipewire
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 19 22:35:59 2026
InstallationDate: Installed on 2026-09-25 (25 days ago)
InstallationMedia: Ubuntu 26.04.1 LTS "Resolute Raccoon" - Release amd64
(20260826)
MachineType: LENOVO 20AMS19100
ProcEnviron:
LANG=es_ES.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-7.0.0-38-generic
root=UUID=3bc1e362-ec2c-4bb4-96c1-189873600ba3 ro quiet splash
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 03/17/2020
dmi.bios.release: 2.49
dmi.bios.vendor: LENOVO
dmi.bios.version: GIET99WW (2.49 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20AMS19100
dmi.board.vendor: LENOVO
dmi.board.version: 0B98401 PRO
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Not Available
dmi.ec.firmware.release: 1.17
dmi.modalias:
dmi:bvnLENOVO:bvrGIET99WW(2.49):bd03/17/2020:br2.49:efr1.17:svnLENOVO:pn20AMS19100:pvrThinkPadX240:rvnLENOVO:rn20AMS19100:rvr0B98401PRO:cvnLENOVO:ct10:cvrNotAvailable:skuLENOVO_MT_20AM_BU_Think_FM_ThinkPadX240:pfaThinkPadX240:
dmi.product.family: ThinkPad X240
dmi.product.name: 20AMS19100
dmi.product.sku: LENOVO_MT_20AM_BU_Think_FM_ThinkPad X240
dmi.product.version: ThinkPad X240
dmi.sys.vendor: LENOVO
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2171463
Title:
audio issues via HDMI
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