[Bug 2158514] [NEW] [Dell Vostro 3520] CS8409/CS42L42 headset mic regression: works on 6.17.0-20, broken on 6.17.0-35 (HWE 24.04)

Public bug reported: The 3.5mm combo-jack headset microphone stopped working after a kernel update on a Dell Vostro 3520 (PCI SSID 1028:0b94, codec CS8409/CS42L42). == Summary == - Wired headset mic works correctly on 6.17.0-20.20~24.04.1-generic - Wired headset mic produces only silence on 6.17.0-35.35~24.04.1-generic - Internal mic and all audio output work on both kernels - This is a clean A/B regression between these two HWE point releases == Steps to reproduce (on -35) == 1. Plug a headset into the 3.5mm combo jack 2. Record: arecord -d 5 -f cd test.wav && aplay test.wav 3. Result: silence. No signal in pavucontrol input meter either. The 'Mic' ALSA control has a volume slider but no capture switch, and no separate headset-mic source appears in PipeWire. == Investigation already done == Both kernels are built on the same mainline stable base (6.17.13). The CS8409 codec init is BIT-IDENTICAL on good and bad kernels: picked fixup for PCI SSID 1028:0b94 Internal Mic=0x44 Mic=0x34 i2c-designware enumeration is also identical. So the regression is NOT in the cs8409 codec driver or its i2c path -- the codec is configured the same way on both. The break appears to be in the ALSA/HDA core capture path or another subsystem between -20 and -35. There are 926 commits between the two tags; none touch sound/hda/codecs/cirrus/ or patch_cs8409.*. Candidates worth checking in the HDA/i2c/gpio area include: 83827930c184 i2c: designware: Disable SMBus interrupts ... 687ba06f49b2 gpiolib: acpi: Add quirk for Dell Precision 7780 I can build kernels and run a full git bisect between Ubuntu-hwe-6.17-6.17.0-20.20_24.04.1 (good) and Ubuntu-hwe-6.17-6.17.0-35.35_24.04.1 (bad) if that would help. Possibly related historical bugs: LP #1972815, LP #1918378. NOTE: Reported manually because the system runs Zorin OS (Ubuntu 24.04 base) and apport refused the kernel as a non-official package. The affected kernel is the standard Ubuntu HWE 6.17 kernel. Logs (uname, version_signature, dmesg, lspci -vvnn) are attached. == System == - Hardware: Dell Vostro 3520 - Codec: CS8409 / CS42L42, PCI SSID 1028:0b94 - Distro: Zorin OS (Ubuntu 24.04 base), HWE 6.17 kernel - Good: 6.17.0-20.20~24.04.1-generic - Bad: 6.17.0-35.35~24.04.1-generic ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are subscribed to linux in Ubuntu. Matching subscriptions: Bgg, Bmail, Nb https://bugs.launchpad.net/bugs/2158514 Title: [Dell Vostro 3520] CS8409/CS42L42 headset mic regression: works on 6.17.0-20, broken on 6.17.0-35 (HWE 24.04) Status in linux package in Ubuntu: New Bug description: The 3.5mm combo-jack headset microphone stopped working after a kernel update on a Dell Vostro 3520 (PCI SSID 1028:0b94, codec CS8409/CS42L42). == Summary == - Wired headset mic works correctly on 6.17.0-20.20~24.04.1-generic - Wired headset mic produces only silence on 6.17.0-35.35~24.04.1-generic - Internal mic and all audio output work on both kernels - This is a clean A/B regression between these two HWE point releases == Steps to reproduce (on -35) == 1. Plug a headset into the 3.5mm combo jack 2. Record: arecord -d 5 -f cd test.wav && aplay test.wav 3. Result: silence. No signal in pavucontrol input meter either. The 'Mic' ALSA control has a volume slider but no capture switch, and no separate headset-mic source appears in PipeWire. == Investigation already done == Both kernels are built on the same mainline stable base (6.17.13). The CS8409 codec init is BIT-IDENTICAL on good and bad kernels: picked fixup for PCI SSID 1028:0b94 Internal Mic=0x44 Mic=0x34 i2c-designware enumeration is also identical. So the regression is NOT in the cs8409 codec driver or its i2c path -- the codec is configured the same way on both. The break appears to be in the ALSA/HDA core capture path or another subsystem between -20 and -35. There are 926 commits between the two tags; none touch sound/hda/codecs/cirrus/ or patch_cs8409.*. Candidates worth checking in the HDA/i2c/gpio area include: 83827930c184 i2c: designware: Disable SMBus interrupts ... 687ba06f49b2 gpiolib: acpi: Add quirk for Dell Precision 7780 I can build kernels and run a full git bisect between Ubuntu-hwe-6.17-6.17.0-20.20_24.04.1 (good) and Ubuntu-hwe-6.17-6.17.0-35.35_24.04.1 (bad) if that would help. Possibly related historical bugs: LP #1972815, LP #1918378. NOTE: Reported manually because the system runs Zorin OS (Ubuntu 24.04 base) and apport refused the kernel as a non-official package. The affected kernel is the standard Ubuntu HWE 6.17 kernel. Logs (uname, version_signature, dmesg, lspci -vvnn) are attached. == System == - Hardware: Dell Vostro 3520 - Codec: CS8409 / CS42L42, PCI SSID 1028:0b94 - Distro: Zorin OS (Ubuntu 24.04 base), HWE 6.17 kernel - Good: 6.17.0-20.20~24.04.1-generic - Bad: 6.17.0-35.35~24.04.1-generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2158514/+subscriptions