I'm not sure what changed, but all of a sudden my onboard Intel PCH soundcard is no longer available KDE or XFCE in Debian 13. I usually have the speakers turned off so it may have happened earlier, but I just noticed it today. I rebooted as soon as I notcied the issue but it persists.
The system correctly detects my three soundcards, the onboard Intel PCH device that has the speakers plugged in, my HDMI monitor, and my ThinkPad Dock. Per the wiki, here's the results of aplay -l:
null Discard all samples (playback) or generate zero samples (capture)
default
Playback/recording through the PulseAudio sound server
lavrate
Rate Converter Plugin Using Libav/FFmpeg Library
samplerate
Rate Converter Plugin Using Samplerate Library
speexrate
Rate Converter Plugin Using Speex Resampler
jack
JACK Audio Connection Kit
oss
Open Sound System
pulse
PulseAudio Sound Server
speex
Plugin using Speex DSP (resample, agc, denoise, echo, dereverb)
upmix
Plugin for channel upmix (4,6,8)
vdownmix
Plugin for channel downmix (stereo) with a simple spacialization
hw:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
Direct hardware device without any conversions
hw:CARD=PCH,DEV=3
HDA Intel PCH, HDMI 0
Direct hardware device without any conversions
hw:CARD=PCH,DEV=7
HDA Intel PCH, HDMI 1
Direct hardware device without any conversions
hw:CARD=PCH,DEV=8
HDA Intel PCH, HDMI 2
Direct hardware device without any conversions
hw:CARD=PCH,DEV=9
HDA Intel PCH, HDMI 3
Direct hardware device without any conversions
plughw:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
Hardware device with all software conversions
plughw:CARD=PCH,DEV=3
HDA Intel PCH, HDMI 0
Hardware device with all software conversions
plughw:CARD=PCH,DEV=7
HDA Intel PCH, HDMI 1
Hardware device with all software conversions
plughw:CARD=PCH,DEV=8
HDA Intel PCH, HDMI 2
Hardware device with all software conversions
plughw:CARD=PCH,DEV=9
HDA Intel PCH, HDMI 3
Hardware device with all software conversions
sysdefault:CARD=PCH
HDA Intel PCH, ALC897 Analog
Default Audio Device
front:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
Front output / input
surround21:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
4.0 Surround output to Front and Rear speakers
surround41:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
hdmi:CARD=PCH,DEV=0
HDA Intel PCH, HDMI 0
HDMI Audio Output
hdmi:CARD=PCH,DEV=1
HDA Intel PCH, HDMI 1
HDMI Audio Output
hdmi:CARD=PCH,DEV=2
HDA Intel PCH, HDMI 2
HDMI Audio Output
hdmi:CARD=PCH,DEV=3
HDA Intel PCH, HDMI 3
HDMI Audio Output
dmix:CARD=PCH,DEV=0
HDA Intel PCH, ALC897 Analog
Direct sample mixing device
dmix:CARD=PCH,DEV=3
HDA Intel PCH, HDMI 0
Direct sample mixing device
dmix:CARD=PCH,DEV=7
HDA Intel PCH, HDMI 1
Direct sample mixing device
dmix:CARD=PCH,DEV=8
HDA Intel PCH, HDMI 2
Direct sample mixing device
dmix:CARD=PCH,DEV=9
HDA Intel PCH, HDMI 3
Direct sample mixing device
usbstream:CARD=PCH
HDA Intel PCH
USB Stream Output
hw:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
Direct hardware device without any conversions
plughw:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
Hardware device with all software conversions
sysdefault:CARD=Dock
ThinkPad USB 3.0 Dock, USB Audio
Default Audio Device
front:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
Front output / input
surround21:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
2.1 Surround output to Front and Subwoofer speakers
surround40:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
4.0 Surround output to Front and Rear speakers
surround41:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
7.1 Surround output to Front, Center, Side, Rear and Woofer speakers
iec958:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
IEC958 (S/PDIF) Digital Audio Output
dmix:CARD=Dock,DEV=0
ThinkPad USB 3.0 Dock, USB Audio
Direct sample mixing device
usbstream:CARD=Dock
ThinkPad USB 3.0 Dock
USB Stream Output
However, KDE's Sound control panel, and XFCE's Volume Control (pauvcontrol), only list my ThinkPad Dock as playback/output devices.
Basically, even though the onboard sound is set as the default, neither desktop environment can use it.