How default device is chosen/could be configured on Linux?

[yarikoptic]

I have a laptop with GNU/Linux Debian (stable/testing/unstable mix) with pulseaudio. sounddevice seems to take the first device in the listing as the default for output, not pulseaudio, for output even if that device (HDMI) is not plugged in.

Interestingly, when HDMI was plugged in into external monitor (with audio speakers) sounddevice showed:

❯ ./examples/play_long_file.py --list-devices
< 0 HDA NVidia: HDMI 1 (hw:0,7), ALSA (0 in, 8 out)
  1 HDA NVidia: HDMI 2 (hw:0,8), ALSA (0 in, 8 out)
  2 HDA NVidia: HDMI 3 (hw:0,9), ALSA (0 in, 8 out)
> 3 sof-hda-dsp: - (hw:1,7), ALSA (2 in, 0 out)
  4 sof-hda-dsp: - (hw:1,31), ALSA (0 in, 2 out)
  5 pipewire, ALSA (64 in, 64 out)
  6 pulse, ALSA (32 in, 32 out)

and after I unplugged HDMI, it found more devices but kept 0th HDMI as the default:

❯ ./examples/play_long_file.py --list-devices
< 0 HDA NVidia: HDMI 0 (hw:0,3), ALSA (0 in, 8 out)
  1 HDA NVidia: HDMI 1 (hw:0,7), ALSA (0 in, 8 out)
  2 HDA NVidia: HDMI 2 (hw:0,8), ALSA (0 in, 8 out)
  3 HDA NVidia: HDMI 3 (hw:0,9), ALSA (0 in, 8 out)
> 4 sof-hda-dsp: - (hw:1,7), ALSA (2 in, 0 out)
  5 sof-hda-dsp: - (hw:1,31), ALSA (0 in, 2 out)
  6 hdmi, ALSA (0 in, 8 out)
  7 pipewire, ALSA (64 in, 64 out)
  8 pulse, ALSA (32 in, 32 out)

I wonder how I could configure my system directly to help sounddevice to choose correct "device" for output to be pulse?

[yarikoptic]

BTW, my

❯ cat ~/.asoundrc
pcm.!default {
    type plug
    slave { pcm "pulse" }
}

pcm.pulse {
    type pulse
}

ctl.mixer0 {
    type hw
    card 0
}

so I was expecting pulse to be default and then its defaults to be chosen

❯ pactl list short sinks
57	alsa_output.pci-0000_00_1f.3-platform-skl_hda_dsp_generic.HiFi__HDMI3__sink	PipeWire	s24-32le 2ch 48000Hz	IDLE
58	alsa_output.pci-0000_00_1f.3-platform-skl_hda_dsp_generic.HiFi__HDMI2__sink	PipeWire	s24-32le 2ch 48000Hz	IDLE
59	alsa_output.pci-0000_00_1f.3-platform-skl_hda_dsp_generic.HiFi__HDMI1__sink	PipeWire	s24-32le 2ch 48000Hz	IDLE
60	alsa_output.pci-0000_00_1f.3-platform-skl_hda_dsp_generic.HiFi__Speaker__sink	PipeWire	s32le 2ch 48000Hz	IDLE
1173	bluez_output.50_C2_75_F4_9D_9E.1	PipeWire	s16le 2ch 48000Hz	IDLE
❯ pactl info | grep 'Default Sink'
Default Sink: alsa_output.pci-0000_00_1f.3-platform-skl_hda_dsp_generic.HiFi__Speaker__sink

I guess there might be more to it to instruct portaudio (which I guess what drives sounddevice choises here) to use pulse audio? (My foo is not strong in the kitchen of ALSA + portaudio + pulseaudio + pipewire on top ;) )

[yarikoptic]

woohoo -- moving that .asoundrc aside just made things work sensibly

❯ mv ~/.asoundrc ~/.asoundrc.aside2
❯ python3 -m sounddevice
  0 HDA NVidia: HDMI 0 (hw:0,3), ALSA (0 in, 8 out)
  1 HDA NVidia: HDMI 1 (hw:0,7), ALSA (0 in, 8 out)
  2 HDA NVidia: HDMI 2 (hw:0,8), ALSA (0 in, 8 out)
  3 HDA NVidia: HDMI 3 (hw:0,9), ALSA (0 in, 8 out)
  4 sof-hda-dsp: - (hw:1,7), ALSA (2 in, 0 out)
  5 sof-hda-dsp: - (hw:1,31), ALSA (0 in, 2 out)
  6 hdmi, ALSA (0 in, 8 out)
  7 pipewire, ALSA (64 in, 64 out)
  8 pulse, ALSA (32 in, 32 out)
* 9 default, ALSA (64 in, 64 out)

I will keep this as a solution for now although I think there is still some more oddity (e.g. portaudio silently not recognizing this fancy asoundrc).