Bug#976298: Internal microphone not detected on Thinkpad T14 Gen 1

[Thibault Vataire <vatairethibault@no-log.org>]

Package: linux-image-5.9.0-0.bpo.2-amd64-unsigned
Version: 5.9.6-1~bpo10+1

No driver is found for Renoir audio processor in buster-backports 5.9 kernel :

$ lshw -c multimedia
  *-usb                     
       description: Vidéo
       produit: Integrated Camera
       fabriquant: Chicony Electronics Co.,Ltd.
       identifiant matériel: 2
       information bus: usb@2:2
       version: 58.18
       numéro de série: 0001
       fonctionnalités: usb-2.01
       configuration: driver=uvcvideo maxpower=500mA speed=480Mbit/s
  *-multimedia:0
       description: Audio device
       produit: Advanced Micro Devices, Inc. [AMD/ATI]
       fabriquant: Advanced Micro Devices, Inc. [AMD/ATI]
       identifiant matériel: 0.1
       information bus: pci@0000:07:00.1
       version: 00
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: pm pciexpress msi bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       ressources: irq:100 mémoire:fd3c8000-fd3cbfff
  *-multimedia:1 NON-RÉCLAMÉ
       description: Multimedia controller
       produit: Advanced Micro Devices, Inc. [AMD]
       fabriquant: Advanced Micro Devices, Inc. [AMD]
       identifiant matériel: 0.5
       information bus: pci@0000:07:00.5
       version: 01
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: pm pciexpress msi cap_list
       configuration: latency=0
       ressources: mémoire:fd380000-fd3bffff
  *-multimedia:2
       description: Audio device
       produit: Advanced Micro Devices, Inc. [AMD]
       fabriquant: Advanced Micro Devices, Inc. [AMD]
       identifiant matériel: 0.6
       information bus: pci@0000:07:00.6
       version: 00
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: pm pciexpress msi bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       ressources: irq:101 mémoire:fd3c0000-fd3c7fff

$ lspci -k -s 07:00.5
07:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] Raven/Raven2/FireFlight/Renoir Audio Processor (rev 01)
	Subsystem: Lenovo Raven/Raven2/FireFlight/Renoir Audio Processor


But on a custom 5.9.11 kernel with "AMD Audio Coprocessor - Renoir support" and "AMD Renoir support for DMIC" enabled :

$ lshw -c multimedia
  *-multimedia:0            
       description: Audio device
       produit: Advanced Micro Devices, Inc. [AMD/ATI]
       fabriquant: Advanced Micro Devices, Inc. [AMD/ATI]
       identifiant matériel: 0.1
       information bus: pci@0000:07:00.1
       version: 00
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       ressources: irq:120 mémoire:fd3c8000-fd3cbfff
  *-multimedia:1
       description: Multimedia controller
       produit: Advanced Micro Devices, Inc. [AMD]
       fabriquant: Advanced Micro Devices, Inc. [AMD]
       identifiant matériel: 0.5
       information bus: pci@0000:07:00.5
       version: 01
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: bus_master cap_list
       configuration: driver=snd_rn_pci_acp3x latency=0
       ressources: irq:102 mémoire:fd380000-fd3bffff
  *-multimedia:2
       description: Audio device
       produit: Advanced Micro Devices, Inc. [AMD]
       fabriquant: Advanced Micro Devices, Inc. [AMD]
       identifiant matériel: 0.6
       information bus: pci@0000:07:00.6
       version: 00
       bits: 32 bits
       horloge: 33MHz
       fonctionnalités: bus_master cap_list
       configuration: driver=snd_hda_intel latency=0
       ressources: irq:121 mémoire:fd3c0000-fd3c7fff

$ lspci -k -s 07:00.5
07:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] Raven/Raven2/FireFlight/Renoir Audio Processor (rev 01)
	Subsystem: Lenovo Raven/Raven2/FireFlight/Renoir Audio Processor
	Kernel driver in use: snd_rn_pci_acp3x
	Kernel modules: snd_rn_pci_acp3x


Once the Renoir audio processor enabled, the internal microphone is visible and functionnal.

I suggest to enable "AMD Audio Coprocessor - Renoir support" and "AMD Renoir support for DMIC" in upcoming kernels.


Miscellaneous informations :

$ lsb_release -d
Description:	Debian GNU/Linux 10 (buster)

# dmidecode -s system-manufacturer; dmidecode -s system-product-name; dmidecode -s system-version
LENOVO
20UDCTO1WW
ThinkPad T14 Gen 1