Arch Linux

markand

Member

Registered: 2015-04-09

Posts: 28

[solved] No DisplayPort audio with Thinkpad USB-C dock

Hi there,

I'm running Arch on a Thinkpad T15 Gen1 (2021) with a USB-C dock. In pulsemixer or any other PulseAudio graphical application (like GNOME) there is only a USB-C audio output so I guess this is the jack on the front of the USB-C dock. However I'd like to use the DisplayPort audio (from the dock itself) output instead which works fine when running under Windows.

This is the cards that are listed:

$ aplay -l 
**** List of PLAYBACK Hardware Devices ****
card 0: Audio [ThinkPad USB-C Dock Audio], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ pacmd list-cards
1 card(s) available.
    index: 0
	name: <alsa_card.usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00>
	driver: <module-alsa-card.c>
	owner module: 6
	properties:
		alsa.card = "0"
		alsa.card_name = "ThinkPad USB-C Dock Audio"
		alsa.long_card_name = "Lenovo ThinkPad USB-C Dock Audio at usb-0000:00:14.0-2.4.2.3, full speed"
		alsa.driver_name = "snd_usb_audio"
		device.bus_path = "pci-0000:00:14.0-usb-0:2.4.2.3:1.0"
		sysfs.path = "/devices/pci0000:00/0000:00:14.0/usb1/1-2/1-2.4/1-2.4.2/1-2.4.2.3/1-2.4.2.3:1.0/sound/card0"
		udev.id = "usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00"
		device.bus = "usb"
		device.vendor.id = "17ef"
		device.vendor.name = "Lenovo"
		device.product.id = "3063"
		device.product.name = "ThinkPad Dock Audio"
		device.serial = "Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000"
		device.string = "0"
		device.description = "ThinkPad Dock Audio"
		module-udev-detect.discovered = "1"
		device.icon_name = "audio-card-usb"
	profiles:
		input:mono-fallback: Mono Input (priority 1, available: unknown)
		output:analog-stereo: Analog Stereo Output (priority 6500, available: unknown)
		output:analog-stereo+input:mono-fallback: Analog Stereo Output + Mono Input (priority 6501, available: unknown)
		output:iec958-stereo: Digital Stereo (IEC958) Output (priority 5500, available: unknown)
		output:iec958-stereo+input:mono-fallback: Digital Stereo (IEC958) Output + Mono Input (priority 5501, available: unknown)
		output:iec958-ac3-surround-51: Digital Surround 5.1 (IEC958/AC3) Output (priority 300, available: unknown)
		output:iec958-ac3-surround-51+input:mono-fallback: Digital Surround 5.1 (IEC958/AC3) Output + Mono Input (priority 301, available: unknown)
		off: Off (priority 0, available: unknown)
	active profile: <output:analog-stereo+input:mono-fallback>
	sinks:
		alsa_output.usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00.analog-stereo/#0: ThinkPad Dock Audio Analog Stereo
	sources:
		alsa_output.usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00.analog-stereo.monitor/#0: Monitor of ThinkPad Dock Audio Analog Stereo
		alsa_input.usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00.mono-fallback/#1: ThinkPad Dock Audio Mono
	ports:
		analog-input-mic: Microphone (priority 8700, latency offset 0 usec, available: unknown)
			properties:
				device.icon_name = "audio-input-microphone"
		analog-output: Analog Output (priority 9900, latency offset 0 usec, available: unknown)
			properties:
				
		iec958-stereo-output: Digital Output (S/PDIF) (priority 0, latency offset 0 usec, available: unknown)
			properties:

Do I miss anything that I must do to get DisplayPort audio output?

Last edited by markand (2022-10-10 06:47:04)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 23,935

Re: [solved] No DisplayPort audio with Thinkpad USB-C dock

Tried switching ot the output:iec958-stereo or ac3-surround profiles? These are normally "digital" and it's likely it logcally maps this accordingly in general the "device" needs to be responsible for announcing/mapping this properly. So if this switch doesn't help then it is not sufficiently providing USB access to it's features, so you'd need to either have a toggle in HW or potential custom code. Do you know whether the dock uses a proprietary/non default driver on Windows?

Maybe also post

amixer -c0

Last edited by V1del (2022-02-24 12:40:34)

markand

Member

Registered: 2015-04-09

Posts: 28

Re: [solved] No DisplayPort audio with Thinkpad USB-C dock

Thanks for your reply. I've tried all profiles with no luck. Using for example:

pacmd set-card-profile alsa_card.usb-Lenovo_ThinkPad_USB-C_Dock_Audio_000000000000-00 output:iec958-stereo

After that, trying to adjust the volume (or seeing through GNOME) it listed as S/PDIF, which definitely isn't DisplayPort.

Here's the result of amixer:

$ amixer -c0
Simple mixer control 'PCM',0
  Capabilities: pvolume pswitch pswitch-joined
  Playback channels: Front Left - Front Right
  Limits: Playback 0 - 50
  Mono:
  Front Left: Playback 50 [100%] [0.00dB] [on]
  Front Right: Playback 50 [100%] [0.00dB] [on]
Simple mixer control 'Mic',0
  Capabilities: cvolume cvolume-joined cswitch cswitch-joined
  Capture channels: Mono
  Limits: Capture 0 - 30
  Mono: Capture 17 [57%] [-13.00dB] [on]
Simple mixer control 'Auto Gain Control',0
  Capabilities: pswitch pswitch-joined
  Playback channels: Mono
  Mono: Playback [off]

Last edited by markand (2022-02-25 12:08:35)

markand

Member

Registered: 2015-04-09

Posts: 28

Re: [solved] No DisplayPort audio with Thinkpad USB-C dock

Hi, I've finally fixed the issue by installing the sof-firmware package which was missing.