Public bug reported: The built-in microphone on a Dell Pro Precision 7 16 (PW716260) records only digital silence (every sample is 0). Speakers, headphones, HDMI audio and the headset jack mic are detected normally.
Release: Ubuntu 24.04.5 LTS (Dell OEM image) Kernel: Ubuntu 7.0.0-38.38~24.04.4-generic 7.0.14 (linux-generic-hwe-24.04). linux-oem-24.04d 7.0.0-28.28~24.04.1 is also installed. BIOS: 1.5.0 (2026-07-17), the latest offered by fwupd/LVFS Audio: Intel Panther Lake [8086:e328], SOF SoundWire, Cirrus cs42l45 (headset + DMIC) and 4x cs35l56 amps Card components: hs:cs42l45 mic:cs42l45-dmic spk:cs35l56 Packages: alsa-ucm-conf 1.2.10-1ubuntu5.15, firmware-sof-signed 2023.12.1-1ubuntu1.11, linux-firmware 20240318.git3b128b60.0ubuntu3.1 (all up to date) Expected: the internal microphone captures audio. Actual: capture from the "Microphones" source returns all-zero samples. This happens both through PipeWire and directly from ALSA (arecord -D hw:1,4). The microphone is not muted anywhere: the cs42l45 FU 113 switch is on, volume is at maximum, the mic-mute LED is off, and the PipeWire source is unmuted. Toggling the mic-mute key does not change it. The microphone is enabled in BIOS. The PCM device and UCM "Mic" device both exist, and the stream opens without errors. Relevant kernel log: sdca_class sdw:0:0:01fa:4245:01: SWFT not available sof-audio-pci-intel-ptl 0000:00:1f.3: No SoundWire machine driver found for the ACPI-reported configuration: sof-audio-pci-intel-ptl 0000:00:1f.3: Use SoundWire default machine driver with function topologies snd_soc_sdca_class_function snd_soc_sdca.SmartMic.0: loading SWF: 1fa-2-1 snd_soc_sdca_class_function snd_soc_sdca.SmartMic.0: loading SWF: 1fa-42450005-1301 sof-audio-pci-intel-ptl 0000:00:1f.3: loading topology 1: intel/sof-ipc4-tplg/sof-sdca-mic-id4.tplg There are no PDE or -110 errors. The machine falls back to the default SoundWire machine driver with function topologies, and the DMIC path produces silence. Similar reports exist for other Panther Lake + cs42l45 machines (ThinkPad X1 Carbon Gen 14, Dell XPS 14/16), e.g. https://github.com/omacom/omarchy/issues/6001. Upstream CS42L45 entries for sdw_utils were posted in April 2026 (tested on a Dell XPS 14) and may not be in this kernel. Attached: mic-bug-logs.txt, which contains version.log, lsb_release, lspci -vnvn, ALSA/UCM info and audio-related kernel messages, in labelled sections. ** Affects: linux (Ubuntu) Importance: Undecided Status: New ** Attachment added: "contains version.log, lsb_release, lspci -vnvn, ALSA/UCM info and audio-related kernel messages, in labelled sections." https://bugs.launchpad.net/bugs/2171518/+attachment/6011052/+files/mic-bug-logs.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2171518 Title: Internal DMIC records only silence on Dell Pro Precision 7 16 (Panther Lake, cs42l45) - "No SoundWire machine driver found" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2171518/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
