vc4.ko brings unusable&unstable ALSA sinks

[Diederik de Haas]

On donderdag 1 april 2021 18:18:14 CEST Diederik de Haas wrote:
> The Debian kernel was also upgraded to 5.10.26 and after reboot it all still
> seems to work, apart from not hearing any sounds, either through mpd or
> paplay.
> I have "blacklist snd_bcm2835" in /etc/modprobe.d/bcm-audio-blacklist.conf
> 
> diederik at rpi-mpd:~$ pactl list cards
> Card #0
>         Name: alsa_card.platform-3f902000.hdmi
>         Driver: module-alsa-card.c
>         Owner Module: 6
>         Properties:
>                 alsa.card = "0"
>                 alsa.card_name = "vc4-hdmi"
>                 alsa.long_card_name = "vc4-hdmi"
>                 alsa.driver_name = "vc4"
>                 device.bus_path = "platform-3f902000.hdmi"
>                 sysfs.path = "/devices/platform/soc/3f902000.hdmi/sound/card0" 
>                 device.form_factor = "internal"
>                 device.string = "0"
>                 device.description = "Built-in Audio"
>                 module-udev-detect.discovered = "1"
>                 device.icon_name = "audio-card"
>         Profiles:
>                 output:hdmi-stereo: Digital Stereo (HDMI) Output (sinks: 1, sources: 0, priority: 5900, available: yes) 
>                 output:hdmi-surround: Digital Surround 5.1 (HDMI) Output (sinks: 1, sources: 0, priority: 800, available: yes) 
>                 output:hdmi-surround71: Digital Surround 7.1 (HDMI) Output (sinks: 1, sources: 0, priority: 800, available: yes) 
>                 off: Off (sinks: 0, sources: 0, priority: 0, available: yes) 
>         Active Profile: output:hdmi-surround71
>         Ports:
>                 hdmi-output-0: HDMI / DisplayPort (type: HDMI, priority: 5900, latency offset: 0 usec, availability unknown) 
>                         Properties:
>                                 device.icon_name = "video-display"
>                                 device.product.name = "SC-1224"
>                         Part of profile(s): output:hdmi-stereo, output:hdmi-surround, output:hdmi-surround71
> 
> The new vc4-hdmi.conf file (from LE) added a 7.1 profile and I've now set
> that as default, but tried the 'hdmi-stereo' too and that didn't produce
> sound either. The 'Ports' shows it correctly detected my AV Receiver :)
> It now has 'type: HDMI' while it was previously 'type: SPDIF'. I don't know
> if that's relevant though.

(In the meantime upgraded to 5.10.0-6-arm64, version 5.10.28-1)

Did an interesting observation:
$ paplay /usr/share/sounds/alsa/Front_Right.wav worked!

So I thought that maybe my music files being served through NFS was a problem, 
so copied various files locally and tried to play that with paplay.
- mp3 file: "Failed to open audio file."
- wav file: appeared to play, but didn't hear anything
- flac file: appeared to play, but didn't hear anything

This is mostly consistent with what I noticed when playing with mpd using ncmpc, 
apart from that the mp3 file also appeared to play, but no audio was heard.
Zooming into the wav files, I ran them through 'file':
$ file Front_Right.wav 
Front_Right.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, mono 48000 Hz
$ file my_music_file.wav
my_music_file.wav: RIFF (little-endian) data, WAVE audio, Microsoft PCM, 16 bit, stereo 44100 Hz

While I wanted to report that the difference was mono vs stereo, 
I now also see 48000 Hz vs 44100 Hz ...

Ohhhh boy ...

Adding the format line to /etc/mpd.conf
audio_output {
        type            "pulse"
        name            "My Pulse Output"
        format          "48000:16:1"
}

And I'm hearing music \o/ with wav, mp3 and flac :)

And the distortion I reported earlier ... gone :D


\o/ w00t \o/

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