[Precision 3630] [Ubuntu 18.04] No sound

Hello everybody out there!

My laboratory has just purchase a Dell Precision 3630 desktop computer for me. According to directives from CNRS, I had to encrypt my hard drives. Also, my laboratory uses the last Ubuntu LTS, being 18.04 nowadays, while the computer came with Ubuntu 16.04. Well, I must say I also do not like standard Ubuntu partitioning. Therefore, I had to reinstall the whole system.

Everything works fine, but for the sound: I cannot get any sound any more, while I did hear some sound when I first powered on the computer with installation from Dell. Therefore, I guess this is nothing but a configuration problem.

In the audio mixer, all I can see is a virtual output (as I am French, everything is in French) :

Here are some information on my system:

$ lsb_release -d ; printenv GDMSESSION ; uname -mrs
Description:	Ubuntu 18.04.1 LTS
gnome
Linux 4.15.0-42-generic x86_64

$ dmesg | grep realtek
[   22.175150] snd_hda_codec_realtek hdaudioC0D0: autoconfig for ALC3234: line_outs=1 (0x1b/0x0/0x0/0x0/0x0) type:line
[   22.175152] snd_hda_codec_realtek hdaudioC0D0:    speaker_outs=1 (0x14/0x0/0x0/0x0/0x0)
[   22.175153] snd_hda_codec_realtek hdaudioC0D0:    hp_outs=1 (0x21/0x0/0x0/0x0/0x0)
[   22.175153] snd_hda_codec_realtek hdaudioC0D0:    mono: mono_out=0x0
[   22.175154] snd_hda_codec_realtek hdaudioC0D0:    inputs:
[   22.175155] snd_hda_codec_realtek hdaudioC0D0:      Headset Mic=0x19

$ lsmod | grep realtek
snd_hda_codec_realtek   106496  1
snd_hda_codec_generic    73728  1 snd_hda_codec_realtek
snd_hda_codec         126976  4 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec_realtek
snd_hda_core           81920  5 snd_hda_codec_generic,snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek
snd                    81920  27 snd_hda_codec_generic,snd_seq,snd_seq_device,snd_hda_codec_hdmi,snd_hwdep,snd_hda_intel,snd_hda_codec,snd_hda_codec_realtek,snd_timer,snd_pcm,snd_rawmidi

$ aplay -l 
**** Liste des Périphériques Matériels PLAYBACK ****
carte 0: PCH [HDA Intel PCH], périphérique 0: ALC3234 Analog [ALC3234 Analog]
  Sous-périphériques: 0/1
  Sous-périphérique #0: subdevice #0
carte 0: PCH [HDA Intel PCH], périphérique 3: HDMI 0 [HDMI 0]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 0: PCH [HDA Intel PCH], périphérique 7: HDMI 1 [HDMI 1]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 0: PCH [HDA Intel PCH], périphérique 8: HDMI 2 [HDMI 2]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 0: PCH [HDA Intel PCH], périphérique 9: HDMI 3 [HDMI 3]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 0: PCH [HDA Intel PCH], périphérique 10: HDMI 4 [HDMI 4]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: HDMI [HDA ATI HDMI], périphérique 3: HDMI 0 [HDMI 0]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: HDMI [HDA ATI HDMI], périphérique 7: HDMI 1 [HDMI 1]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: HDMI [HDA ATI HDMI], périphérique 8: HDMI 2 [HDMI 2]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: HDMI [HDA ATI HDMI], périphérique 9: HDMI 3 [HDMI 3]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0
carte 1: HDMI [HDA ATI HDMI], périphérique 10: HDMI 4 [HDMI 4]
  Sous-périphériques: 1/1
  Sous-périphérique #0: subdevice #0

$ cat /proc/asound/card0/codec* | grep Codec
Codec: Realtek ALC3234
Codec: Intel Kabylake HDMI

$ cat /proc/asound/version 
Advanced Linux Sound Architecture Driver Version k4.15.0-42-generic.

$ cat /proc/asound/cards 
 0 [PCH            ]: HDA-Intel - HDA Intel PCH
                      HDA Intel PCH at 0x4000110000 irq 130
 1 [HDMI           ]: HDA-Intel - HDA ATI HDMI
                      HDA ATI HDMI at 0xa2060000 irq 129

$ cat /proc/asound/devices 
  1:        : sequencer
  2: [ 1]   : control
  3: [ 1- 3]: digital audio playback
  4: [ 1- 7]: digital audio playback
  5: [ 1- 8]: digital audio playback
  6: [ 1- 9]: digital audio playback
  7: [ 1-10]: digital audio playback
  8: [ 1- 0]: hardware dependent
  9: [ 0]   : control
 10: [ 0- 0]: digital audio playback
 11: [ 0- 0]: digital audio capture
 12: [ 0- 3]: digital audio playback
 13: [ 0- 7]: digital audio playback
 14: [ 0- 8]: digital audio playback
 15: [ 0- 9]: digital audio playback
 16: [ 0-10]: digital audio playback
 17: [ 0- 0]: hardware dependent
 18: [ 0- 2]: hardware dependent
 33:        : timer

$ cat /proc/asound/timers 
G0: system timer : 4000.000us (10000000 ticks)
G3: HR timer : 0.001us (1000000000 ticks)
  Client sequencer queue -1 : stopped
P0-0-0: PCM playback 0-0-0 : SLAVE
P0-0-1: PCM capture 0-0-1 : SLAVE
P0-3-0: PCM playback 0-3-0 : SLAVE
P0-7-0: PCM playback 0-7-0 : SLAVE
P0-8-0: PCM playback 0-8-0 : SLAVE
P0-9-0: PCM playback 0-9-0 : SLAVE
P0-10-0: PCM playback 0-10-0 : SLAVE
P1-3-0: PCM playback 1-3-0 : SLAVE
P1-7-0: PCM playback 1-7-0 : SLAVE
P1-8-0: PCM playback 1-8-0 : SLAVE
P1-9-0: PCM playback 1-9-0 : SLAVE
P1-10-0: PCM playback 1-10-0 : SLAVE

$ cat /proc/asound/pcm 
00-00: ALC3234 Analog : ALC3234 Analog : playback 1 : capture 1
00-03: HDMI 0 : HDMI 0 : playback 1
00-07: HDMI 1 : HDMI 1 : playback 1
00-08: HDMI 2 : HDMI 2 : playback 1
00-09: HDMI 3 : HDMI 3 : playback 1
00-10: HDMI 4 : HDMI 4 : playback 1
01-03: HDMI 0 : HDMI 0 : playback 1
01-07: HDMI 1 : HDMI 1 : playback 1
01-08: HDMI 2 : HDMI 2 : playback 1
01-09: HDMI 3 : HDMI 3 : playback 1
01-10: HDMI 4 : HDMI 4 : playback 1

Well, something is wrong with Pulseaudio configuration, I guess, but I do not know what to do. Does anyone have some suggestion?

Best regards.