PIB - 20200610: Ubuntu 20.04 LTS - ダミー出力になって音が出ない

状況

デスクトップ右上のメニューから「電源オフ/ログアウト」→「サスペンド」してた後、復帰したら音が出なくなってた。
デスクトップ右上のメニューから「設定」→「サウンド」の出力のところで出力デバイスが「ダミー出力」になっていた。

alsamixer 実行してみるとちゃんと HDA Intel PCH は動いているのだが、なぜがデスクトップから見えない。
Ubuntu サウンド ダミー出力」でググってみると
の和訳が見つかる。
なんか、最近この手のソース示してない質悪い和訳ばかり見つかるんだけどなんで?

このスレッド見ると
sudo alsa force-reload
なども見かけたが、alsamixer は HDA Intel PCH 認識しているのでこのレイヤーの障害じゃないっぽい。

他には、
pacmd list-clients
でサウンドカードの一覧が得られる的な話も見かけた。
これは PulseAudio のレイヤー
確認してみると、"HDA NVidia", "USB Device 0x46d:0x994" しかなくて ”HDA Intel PCH" が見当たらない。
$ pacmd list-cards
2 card(s) available.
    index: 0
	name: <alsa_card.pci-0000_01_00.1>
	driver: <module-alsa-card.c>
	owner module: 23
	properties:
		alsa.card = "2"
		alsa.card_name = "HDA NVidia"
		alsa.long_card_name = "HDA NVidia at 0xdf080000 irq 17"
		alsa.driver_name = "snd_hda_intel"
		device.bus_path = "pci-0000:01:00.1"
		sysfs.path = "/devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card2"
		device.bus = "pci"
		device.vendor.id = "10de"
		device.vendor.name = "NVIDIA Corporation"
		device.product.id = "0fba"
		device.product.name = "GM206 High Definition Audio Controller"
		device.string = "2"
		device.description = "GM206 High Definition Audio Controller"
		module-udev-detect.discovered = "1"
		device.icon_name = "audio-card-pci"
	profiles:
		output:hdmi-stereo: Digital Stereo (HDMI) 出力 (priority 5900, available: no)
		output:hdmi-surround: Digital Surround 5.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-surround71: Digital Surround 7.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-stereo-extra1: Digital Stereo (HDMI 2) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra1: Digital Surround 5.1 (HDMI 2) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra1: Digital Surround 7.1 (HDMI 2) 出力 (priority 600, available: no)
		output:hdmi-stereo-extra2: Digital Stereo (HDMI 3) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra2: Digital Surround 5.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra2: Digital Surround 7.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-stereo-extra3: Digital Stereo (HDMI 4) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra3: Digital Surround 5.1 (HDMI 4) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra3: Digital Surround 7.1 (HDMI 4) 出力 (priority 600, available: no)
		off: オフ (priority 0, available: unknown)
	active profile: <off>
	ports:
		hdmi-output-0: HDMI / DisplayPort (priority 5900, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-1: HDMI / DisplayPort 2 (priority 5800, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-2: HDMI / DisplayPort 3 (priority 5700, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-3: HDMI / DisplayPort 4 (priority 5600, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
    index: 1
	name: <alsa_card.usb-046d_0994_46D23700-02>
	driver: <module-alsa-card.c>
	owner module: 24
	properties:
		alsa.card = "1"
		alsa.card_name = "USB Device 0x46d:0x994"
		alsa.long_card_name = "USB Device 0x46d:0x994 at usb-0000:00:14.0-11.1, high speed"
		alsa.driver_name = "snd_usb_audio"
		device.bus_path = "pci-0000:00:14.0-usb-0:11.1:1.2"
		sysfs.path = "/devices/pci0000:00/0000:00:14.0/usb1/1-11/1-11.1/1-11.1:1.2/sound/card1"
		udev.id = "usb-046d_0994_46D23700-02"
		device.bus = "usb"
		device.vendor.id = "046d"
		device.vendor.name = "Logitech, Inc."
		device.product.id = "0994"
		device.product.name = "QuickCam Orbit/Sphere AF"
		device.serial = "046d_0994_46D23700"
		device.form_factor = "webcam"
		device.string = "1"
		device.description = "QuickCam Orbit/Sphere AF"
		module-udev-detect.discovered = "1"
		device.icon_name = "camera-web-usb"
	profiles:
		input:mono-fallback: モノ 入力 (priority 1, available: unknown)
		input:multichannel-input: マルチチャンネル 入力 (priority 1, available: unknown)
		off: オフ (priority 0, available: unknown)
	active profile: <input:multichannel-input>
	sources:
		alsa_input.usb-046d_0994_46D23700-02.multichannel-input/#1: QuickCam Orbit/Sphere AF マルチチャンネル
	ports:
		analog-input-mic: マイク (priority 8700, latency offset 0 usec, available: unknown)
			properties:
				device.icon_name = "audio-input-microphone"
		multichannel-input: マルチチャンネル入力 (priority 0, latency offset 0 usec, available: unknown)
			properties:
				

そこで「pulseaudio ubuntu sound dummy」でググってみると で以下の方法が紹介されていた。
pulseaudio -k

どうもこれが正解だったらしく、
$ pacmd list-cards
4 card(s) available.
    index: 0
	name: <alsa_card.pci-0000_01_00.1>
	driver: <module-alsa-card.c>
	owner module: 7
	properties:
		alsa.card = "2"
		alsa.card_name = "HDA NVidia"
		alsa.long_card_name = "HDA NVidia at 0xdf080000 irq 17"
		alsa.driver_name = "snd_hda_intel"
		device.bus_path = "pci-0000:01:00.1"
		sysfs.path = "/devices/pci0000:00/0000:00:01.0/0000:01:00.1/sound/card2"
		device.bus = "pci"
		device.vendor.id = "10de"
		device.vendor.name = "NVIDIA Corporation"
		device.product.id = "0fba"
		device.product.name = "GM206 High Definition Audio Controller"
		device.string = "2"
		device.description = "GM206 High Definition Audio Controller"
		module-udev-detect.discovered = "1"
		device.icon_name = "audio-card-pci"
	profiles:
		output:hdmi-stereo: Digital Stereo (HDMI) 出力 (priority 5900, available: no)
		output:hdmi-surround: Digital Surround 5.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-surround71: Digital Surround 7.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-stereo-extra1: Digital Stereo (HDMI 2) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra1: Digital Surround 5.1 (HDMI 2) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra1: Digital Surround 7.1 (HDMI 2) 出力 (priority 600, available: no)
		output:hdmi-stereo-extra2: Digital Stereo (HDMI 3) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra2: Digital Surround 5.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra2: Digital Surround 7.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-stereo-extra3: Digital Stereo (HDMI 4) 出力 (priority 5700, available: no)
		output:hdmi-surround-extra3: Digital Surround 5.1 (HDMI 4) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra3: Digital Surround 7.1 (HDMI 4) 出力 (priority 600, available: no)
		off: オフ (priority 0, available: unknown)
	active profile: <off>
	ports:
		hdmi-output-0: HDMI / DisplayPort (priority 5900, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-1: HDMI / DisplayPort 2 (priority 5800, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-2: HDMI / DisplayPort 3 (priority 5700, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-3: HDMI / DisplayPort 4 (priority 5600, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
    index: 1
	name: <alsa_card.usb-046d_0994_46D23700-02>
	driver: <module-alsa-card.c>
	owner module: 8
	properties:
		alsa.card = "1"
		alsa.card_name = "USB Device 0x46d:0x994"
		alsa.long_card_name = "USB Device 0x46d:0x994 at usb-0000:00:14.0-11.1, high speed"
		alsa.driver_name = "snd_usb_audio"
		device.bus_path = "pci-0000:00:14.0-usb-0:11.1:1.2"
		sysfs.path = "/devices/pci0000:00/0000:00:14.0/usb1/1-11/1-11.1/1-11.1:1.2/sound/card1"
		udev.id = "usb-046d_0994_46D23700-02"
		device.bus = "usb"
		device.vendor.id = "046d"
		device.vendor.name = "Logitech, Inc."
		device.product.id = "0994"
		device.product.name = "QuickCam Orbit/Sphere AF"
		device.serial = "046d_0994_46D23700"
		device.form_factor = "webcam"
		device.string = "1"
		device.description = "QuickCam Orbit/Sphere AF"
		module-udev-detect.discovered = "1"
		device.icon_name = "camera-web-usb"
	profiles:
		input:mono-fallback: モノ 入力 (priority 1, available: unknown)
		input:multichannel-input: マルチチャンネル 入力 (priority 1, available: unknown)
		off: オフ (priority 0, available: unknown)
	active profile: <input:multichannel-input>
	sources:
		alsa_input.usb-046d_0994_46D23700-02.multichannel-input/#0: QuickCam Orbit/Sphere AF マルチチャンネル
	ports:
		analog-input-mic: マイク (priority 8700, latency offset 0 usec, available: unknown)
			properties:
				device.icon_name = "audio-input-microphone"
		multichannel-input: マルチチャンネル入力 (priority 0, latency offset 0 usec, available: unknown)
			properties:
				
    index: 2
	name: <alsa_card.usb-046d_0994_56313700-02>
	driver: <module-alsa-card.c>
	owner module: 9
	properties:
		alsa.card = "3"
		alsa.card_name = "USB Device 0x46d:0x994"
		alsa.long_card_name = "USB Device 0x46d:0x994 at usb-0000:00:14.0-11.2, high speed"
		alsa.driver_name = "snd_usb_audio"
		device.bus_path = "pci-0000:00:14.0-usb-0:11.2:1.2"
		sysfs.path = "/devices/pci0000:00/0000:00:14.0/usb1/1-11/1-11.2/1-11.2:1.2/sound/card3"
		udev.id = "usb-046d_0994_56313700-02"
		device.bus = "usb"
		device.vendor.id = "046d"
		device.vendor.name = "Logitech, Inc."
		device.product.id = "0994"
		device.product.name = "QuickCam Orbit/Sphere AF"
		device.serial = "046d_0994_56313700"
		device.form_factor = "webcam"
		device.string = "3"
		device.description = "QuickCam Orbit/Sphere AF"
		module-udev-detect.discovered = "1"
		device.icon_name = "camera-web-usb"
	profiles:
		input:mono-fallback: モノ 入力 (priority 1, available: unknown)
		input:multichannel-input: マルチチャンネル 入力 (priority 1, available: unknown)
		off: オフ (priority 0, available: unknown)
	active profile: <input:multichannel-input>
	sources:
		alsa_input.usb-046d_0994_56313700-02.multichannel-input/#1: QuickCam Orbit/Sphere AF マルチチャンネル
	ports:
		analog-input-mic: マイク (priority 8700, latency offset 0 usec, available: unknown)
			properties:
				device.icon_name = "audio-input-microphone"
		multichannel-input: マルチチャンネル入力 (priority 0, latency offset 0 usec, available: unknown)
			properties:
				
    index: 3
	name: <alsa_card.pci-0000_00_1f.3>
	driver: <module-alsa-card.c>
	owner module: 10
	properties:
		alsa.card = "0"
		alsa.card_name = "HDA Intel PCH"
		alsa.long_card_name = "HDA Intel PCH at 0xdf520000 irq 168"
		alsa.driver_name = "snd_hda_intel"
		device.bus_path = "pci-0000:00:1f.3"
		sysfs.path = "/devices/pci0000:00/0000:00:1f.3/sound/card0"
		device.bus = "pci"
		device.vendor.id = "8086"
		device.vendor.name = "Intel Corporation"
		device.product.id = "a170"
		device.product.name = "100 Series/C230 Series Chipset Family HD Audio Controller"
		device.form_factor = "internal"
		device.string = "0"
		device.description = "内部オーディオ"
		module-udev-detect.discovered = "1"
		device.icon_name = "audio-card-pci"
	profiles:
		input:analog-stereo: アナログステレオ 入力 (priority 65, available: no)
		output:analog-stereo: アナログステレオ 出力 (priority 6500, available: unknown)
		output:analog-stereo+input:analog-stereo: アナログステレオ入出力 (priority 6565, available: no)
		output:hdmi-stereo: Digital Stereo (HDMI) 出力 (priority 5900, available: no)
		output:hdmi-stereo+input:analog-stereo: Digital Stereo (HDMI) 出力 + アナログステレオ 入力 (priority 5965, available: no)
		output:hdmi-surround: Digital Surround 5.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-surround+input:analog-stereo: Digital Surround 5.1 (HDMI) 出力 + アナログステレオ 入力 (priority 865, available: no)
		output:hdmi-surround71: Digital Surround 7.1 (HDMI) 出力 (priority 800, available: no)
		output:hdmi-surround71+input:analog-stereo: Digital Surround 7.1 (HDMI) 出力 + アナログステレオ 入力 (priority 865, available: no)
		output:hdmi-stereo-extra1: Digital Stereo (HDMI 2) 出力 (priority 5700, available: unknown)
		output:hdmi-stereo-extra1+input:analog-stereo: Digital Stereo (HDMI 2) 出力 + アナログステレオ 入力 (priority 5765, available: no)
		output:hdmi-stereo-extra2: Digital Stereo (HDMI 3) 出力 (priority 5700, available: no)
		output:hdmi-stereo-extra2+input:analog-stereo: Digital Stereo (HDMI 3) 出力 + アナログステレオ 入力 (priority 5765, available: no)
		output:hdmi-surround-extra2: Digital Surround 5.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-surround-extra2+input:analog-stereo: Digital Surround 5.1 (HDMI 3) 出力 + アナログステレオ 入力 (priority 665, available: no)
		output:hdmi-surround71-extra2: Digital Surround 7.1 (HDMI 3) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra2+input:analog-stereo: Digital Surround 7.1 (HDMI 3) 出力 + アナログステレオ 入力 (priority 665, available: no)
		output:hdmi-stereo-extra3: Digital Stereo (HDMI 4) 出力 (priority 5700, available: no)
		output:hdmi-stereo-extra3+input:analog-stereo: Digital Stereo (HDMI 4) 出力 + アナログステレオ 入力 (priority 5765, available: no)
		output:hdmi-surround-extra3: Digital Surround 5.1 (HDMI 4) 出力 (priority 600, available: no)
		output:hdmi-surround-extra3+input:analog-stereo: Digital Surround 5.1 (HDMI 4) 出力 + アナログステレオ 入力 (priority 665, available: no)
		output:hdmi-surround71-extra3: Digital Surround 7.1 (HDMI 4) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra3+input:analog-stereo: Digital Surround 7.1 (HDMI 4) 出力 + アナログステレオ 入力 (priority 665, available: no)
		output:hdmi-stereo-extra4: Digital Stereo (HDMI 5) 出力 (priority 5700, available: no)
		output:hdmi-stereo-extra4+input:analog-stereo: Digital Stereo (HDMI 5) 出力 + アナログステレオ 入力 (priority 5765, available: no)
		output:hdmi-surround-extra4: Digital Surround 5.1 (HDMI 5) 出力 (priority 600, available: no)
		output:hdmi-surround-extra4+input:analog-stereo: Digital Surround 5.1 (HDMI 5) 出力 + アナログステレオ 入力 (priority 665, available: no)
		output:hdmi-surround71-extra4: Digital Surround 7.1 (HDMI 5) 出力 (priority 600, available: no)
		output:hdmi-surround71-extra4+input:analog-stereo: Digital Surround 7.1 (HDMI 5) 出力 + アナログステレオ 入力 (priority 665, available: no)
		off: オフ (priority 0, available: unknown)
	active profile: <output:hdmi-stereo-extra1>
	sinks:
		alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1/#0: 内部オーディオ Digital Stereo (HDMI 2)
	sources:
		alsa_output.pci-0000_00_1f.3.hdmi-stereo-extra1.monitor/#2: Monitor of 内部オーディオ Digital Stereo (HDMI 2)
	ports:
		analog-input-front-mic: フロントマイクロフォン (priority 8500, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "audio-input-microphone"
		analog-input-rear-mic: リアマイクロフォン (priority 8200, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "audio-input-microphone"
		analog-input-linein: ラインイン (priority 8100, latency offset 0 usec, available: no)
			properties:
				
		analog-output-lineout: ライン出力 (priority 9000, latency offset 0 usec, available: yes)
			properties:
				
		analog-output-headphones: アナログヘッドフォン (priority 9900, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "audio-headphones"
		hdmi-output-0: HDMI / DisplayPort (priority 5900, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-1: HDMI / DisplayPort 2 (priority 5800, latency offset 0 usec, available: yes)
			properties:
				device.icon_name = "video-display"
				device.product.name = "PLB2403WS"
		hdmi-output-2: HDMI / DisplayPort 3 (priority 5700, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-3: HDMI / DisplayPort 4 (priority 5600, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
		hdmi-output-4: HDMI / DisplayPort 5 (priority 5500, latency offset 0 usec, available: no)
			properties:
				device.icon_name = "video-display"
のように、"HDA Intel PCH" が復活し、「設定」→「サウンド」の出力にある出力デバイスにも「HDMI/DisplayPort2 - 内部オーディオ」が表示され、サウンドが復帰した。