debcrafters-packages team mailing list archive

[Sudhakar Verma <2116889@xxxxxxxxxxxxxxxxxx>]

Thanks for taking the time to report this bug and helping to make Ubuntu
better. We appreciate the difficulties you are facing, but this appears
to be a "regular" (non-security) bug.  I have unmarked it as a security
issue since this bug does not show evidence of allowing attackers to
cross privilege boundaries nor directly cause loss of data/privacy.
Please feel free to report any other bugs you may find.

** Information type changed from Private Security to Public

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https://bugs.launchpad.net/bugs/2116889

Title:
  Internal microphone not working on iMac18,3 (CS8409 codec) in Ubuntu
  24.04.02

Status in alsa-driver package in Ubuntu:
  New

Bug description:
  Internal microphone not working on iMac18,3 with CS8409 codec (Ubuntu
  24.04.02)

  📋 Description
  System:

  Device: Apple iMac18,3 (27", 2017)

  OS: Ubuntu 24.04.2 LTS (Wayland)

  Kernel: 6.11.0-29-generic

  Audio Codec: Cirrus Logic CS8409 / CS42L83

  Driver: snd-hda-codec-cs8409 (manually compiled from egorenar GitHub
  repository)

  ALSA Info: http://alsa-
  project.org/db/?f=47cfd6f15f4b7c5b8bc8110a63b2ebc366be9885

  🔍 Issue
  The internal microphone is detected, but capture input is not functional:

  dmesg detects microphone at NID 0x45

  alsamixer shows “Internal Mic Boost” but no Capture control

  arecord -vv -f cd test.wav produces silence (#+ | 00%)

  PipeWire lists the capture stream but does not receive input

  🧪 Diagnostics
  Tested activation via hda-verb:

  bash
  sudo hda-verb /dev/snd/hwC0D0 0x45 SET_PIN_WIDGET_CONTROL 0x40
  sudo hda-verb /dev/snd/hwC0D0 0x45 SET_AMP_GAIN_MUTE 0x7000
  sudo hda-verb /dev/snd/hwC0D0 0x45 SET_AMP_GAIN_MUTE 0x5000
  All commands returned value = 0x0 (accepted by codec), but input remained inactive.

  Also attempted activation on NID 0x44, with identical results.

  💡 Proposed Solution
  The input path appears physically present but missing software initialization. Suggested fixes:

  Driver patch (patch_cs8409.c):

  Enable NID 0x45 as Internal Mic input

  Properly configure AMP-IN and gain levels

  UCM profile (cs8409-imac18.3):

  Define input stream mapping (capture_FL / capture_FR)

  Include Internal Mic device with boost controls

  Integration with PipeWire via updated ucm2 configuration

  🙋‍♂️ Offer to assist
  I’m happy to test any proposed patches or UCM profiles. I have extensive logs and direct access to affected hardware.

  Thanks to ALSA maintainers and Ubuntu devs for your outstanding work!

  Marek (mahav-t) Ubuntu 24.04 on iMac18,3 (2017)

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