internal microphone stops working

[Janet C <nonaggie@protonmail.com>]

Hello,

I'm running bookworm on a Thinkpad T14s Gen4 AMD and am having an issue with the internal microphone. Using the kernel from bookworm, the microphone doesn't work at all, so I installed kernel 6.12 from backports. Now the microphone works when I boot, but at some point, it stops working until I reboot. I haven't been able to find any pattern in when it stops working. And when it stops, it's still detected (for example, I see it in pavucontrol, and the configuration is unchanged) but it doesn't seem to register any input (in pavucontrol, the VU meter doesn't move, and I can't record audio in any applications). I'm using pipewire.

Any suggestions for how I can go about diagnosing the issue? I've tried restarting pipewire and wireplumber, but that doesn't do anything; the only way I've found to get the microphone working again is to reboot.

Below is the relevant output from pactl list cards; it's the same when the microphone is working and when it isn't working.

Thanks for any ideas,
Janet

Card #45
	Name: alsa_card.pci-0000_c3_00.5-platform-acp_ps_mach
	Driver: alsa
	Owner Module: n/a
	Properties:
		api.acp.auto-port = "false"
		api.acp.auto-profile = "false"
		api.alsa.card = "2"
		api.alsa.card.longname = "LENOVO-21F8CTO1WW-ThinkPadT14sGen4"
		api.alsa.card.name = "acp63"
		api.alsa.path = "hw:2"
		api.alsa.use-acp = "true"
		api.alsa.use-ucm = "false"
		api.dbus.ReserveDevice1 = "Audio2"
		device.api = "alsa"
		device.bus = "pci"
		device.bus_path = "pci-0000:c3:00.5-platform-acp_ps_mach"
		device.description = "ACP/ACP3X/ACP6x Audio Coprocessor"
		device.enum.api = "udev"
		device.icon_name = "audio-card-analog-pci"
		device.name = "alsa_card.pci-0000_c3_00.5-platform-acp_ps_mach"
		device.nick = "acp63"
		device.plugged.usec = "2879455"
		device.product.id = "0x15e2"
		device.product.name = "ACP/ACP3X/ACP6x Audio Coprocessor"
		device.subsystem = "sound"
		sysfs.path = "/devices/pci0000:00/0000:00:08.1/0000:c3:00.5/acp_ps_mach/sound/card2"
		device.vendor.id = "0x1022"
		device.vendor.name = "Advanced Micro Devices, Inc. [AMD]"
		media.class = "Audio/Device"
		factory.id = "14"
		client.id = "33"
		object.id = "45"
		object.serial = "45"
		object.path = "alsa:pcm:2"
		alsa.card = "2"
		alsa.card_name = "acp63"
		alsa.long_card_name = "LENOVO-21F8CTO1WW-ThinkPadT14sGen4"
		alsa.driver_name = "snd_soc_ps_mach"
		device.string = "2"
	Profiles:
		off: Off (sinks: 0, sources: 0, priority: 0, available: yes)
		input:stereo-fallback: Stereo Input (sinks: 0, sources: 1, priority: 51, available: yes)
		pro-audio: Pro Audio (sinks: 0, sources: 1, priority: 1, available: yes)
	Active Profile: input:stereo-fallback
	Ports:
		analog-input: Analog Input (type: Analog, priority: 10000, latency offset: 0 usec, availability unknown)
			Properties:
				port.type = "analog"
				card.profile.port = "0"
			Part of profile(s): input:stereo-fallback