Recently the OS crashed after updating. Then I tried to reinstall Ubuntu. It turns out it can't detect the audio output via the DP port.
Pulse Audio:
The speaker of my monitor works fine. The tricky point is that the speaker works perfectly when I use live Ubuntu from my UFEI USB stick. I have tried both live Ubuntu 22.04 and 22.10. It works on both live Ubuntu versions. I have tried the solutions of similar issues, but they didn't help. I have no idea why the DP port can detect the video in, but not the sound out.
My desktop hardware configuration:
- Monitor: LG UltraWide QHD HDR VA 35WN65C-B
- Graphics card: AMD R9 270
Here is the output of some commands
$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC887-VD Analog [ALC887-VD Analog]
Subdevices: 0/1
$ lspci
00:00.0 Host bridge: Intel Corporation 4th Gen Core Processor DRAM Controller (rev 06)
00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor PCI Express x16 Controller (rev 06)
00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
00:14.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB xHCI (rev 05)
00:16.0 Communication controller: Intel Corporation 8 Series/C220 Series Chipset Family MEI Controller #1 (rev 04)
00:16.3 Serial controller: Intel Corporation 8 Series/C220 Series Chipset Family KT Controller (rev 04)
00:1a.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #2 (rev 05)
00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 05)
00:1c.0 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #1 (rev d5)
00:1c.2 PCI bridge: Intel Corporation 8 Series/C220 Series Chipset Family PCI Express Root Port #3 (rev d5)
00:1c.3 PCI bridge: Intel Corporation 82801 PCI Bridge (rev d5)
00:1d.0 USB controller: Intel Corporation 8 Series/C220 Series Chipset Family USB EHCI #1 (rev 05)
00:1f.0 ISA bridge: Intel Corporation B85 Express LPC Controller (rev 05)
00:1f.2 SATA controller: Intel Corporation 8 Series/C220 Series Chipset Family 6-port SATA Controller 1 [AHCI mode] (rev 05)
00:1f.3 SMBus: Intel Corporation 8 Series/C220 Series Chipset Family SMBus Controller (rev 05)
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Curacao PRO [Radeon R7 370 / R9 270/370 OEM]
01:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Oland/Hainan/Cape Verde/Pitcairn HDMI Audio [Radeon HD 7000 Series]
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06)
04:00.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 41)
$ amixer scontrols
Simple mixer control 'Master',0
Simple mixer control 'Headphone',0
Simple mixer control 'PCM',0
Simple mixer control 'Front',0
Simple mixer control 'Front Mic',0
Simple mixer control 'Front Mic Boost',0
Simple mixer control 'Surround',0
Simple mixer control 'Center',0
Simple mixer control 'LFE',0
Simple mixer control 'Line',0
Simple mixer control 'Line Boost',0
Simple mixer control 'CD',0
Simple mixer control 'Beep',0
Simple mixer control 'Capture',0
Simple mixer control 'Capture',1
Simple mixer control 'Channel Mode',0
Simple mixer control 'Input Source',0
Simple mixer control 'Input Source',1
Simple mixer control 'Loopback Mixing',0
Simple mixer control 'Rear Mic',0
Simple mixer control 'Rear Mic Boost',0
amixer scontrolsthroug [edit] ? – nobody Mar 18 '23 at 18:28