Dennis HilkLinux Fix LabDE

Audio, ALSA & PipeWire

HDMI or DisplayPort audio has no usable sink

Check monitor audio capabilities and HDMI ELD presence before forcing an output profile, especially after docking, cable changes or display sleep.

Editorial source review: Start with the evidenceShare this guide
On this page
  1. Symptoms & scope
  2. Possible causes
  3. Diagnose safely
  4. Evidence-guided next steps
  5. References & review
  6. Related problems

Symptoms & scope

  • The display works but HDMI audio is unavailable or silent.
  • Audio disappears after a display reconnect or wake-up.

Relevant environment

GPU HDMI/DisplayPort audio exposed through ALSA HD-Audio; displays and adapters must advertise audio support.

Recognizable messages (synthetic examples)
snd_hda_codec_hdmi hdaudioC1D0: HDMI: invalid ELD data byte 0

Inspect the actual ELD and cable/receiver chain before treating this as a PipeWire routing error.

Possible causes

These are possible explanations, not a confirmed diagnosis. Several independent faults can coexist.

  • The display or adapter may not provide valid ELD audio capability data, or the monitor may have no audio support.
  • A valid HDMI endpoint can still be deselected, muted or assigned to another connector by session policy.

Diagnose safely

Run one command at a time in the relevant session. Read the explanation first. Uppercase placeholders need your own values; tools and privileges vary by distribution. These commands are displayed here and never executed by the website.

Check 1

Read ALSA playback devices without playing audio; identify the GPU card and HDMI PCM names.

aplay -l

Interpret the result: An HDMI PCM proves driver registration, not a connected receiver. Absence of the GPU card belongs to driver detection.

Check 2

Replace card0 and eld#0.0 with the ELD file for the relevant GPU connector shown under /proc/asound; ordinary read access is usually sufficient.

cat /proc/asound/card0/eld#0.0

Interpret the result: monitor_present, eld_valid, monitor_name and SAD entries describe receiver detection and audio formats. Zero validity or no SAD needs a cable/receiver check before profile forcing.

Evidence-guided next steps

Restore audio-capable receiver detection

If ELD is absent or invalid, confirm the display supports audio, select its proper input and compare a direct known-good HDMI/DP cable without the suspect adapter or dock. Reconnect only after saving work affected by display changes.

Precautions: Some DVI adapters carry no audio. Monitor sleep and hotplug can alter connector numbering, so re-identify the ELD path.

Recovery / rollback: Restore the prior cable/input arrangement if display behavior worsens; keep the working non-HDMI output available.

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Select the valid HDMI route and profile

If ELD is valid with supported audio formats, select the matching HDMI profile and connector in the desktop audio panel, unmute at low volume, and check the monitor’s own volume. Use current device and route IDs if applying wpctl controls.

Precautions: Do not select a different HDMI port merely because it is numbered first. Invalid ELD is not repaired by forcing unsupported formats.

Recovery / rollback: Restore the recorded card profile, route and default sink if the selected endpoint is unsuitable.

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References & review

This guide was prepared from primary project or distribution sources and reviewed on the date shown. This is an editorial source check, not evidence that a fix was reproduced on your hardware. Diagnostic log examples are synthetic fixtures. Version-dependent details must be checked against your installed release.