vc4.ko brings unusable&unstable ALSA sinks

Diederik de Haas didi.debian at
Thu Apr 1 17:18:14 BST 2021

On donderdag 1 april 2021 17:04:46 CEST Dave Stevenson wrote:
> > My question then is: should I use one of these dtoverlays and if so,
> > which?
> Mainline doesn't build dtb files with the appropriate symbols for
> overlays to work, therefore they generally can't be applied.

Thank you.
In a way I wonder 'why not?', but I'll consider that OT and it is also 
'above my paygrade'.

> It should have thew display pipeline (ie vc4.ko) enabled by default
> via the status = "okay"; lines in
> 4-b.dts#L182 for hvs, pixel valves, hdmi, ddc, and a few other blocks.

I hope to learn more about them some day, but I don't really understand 
them (now). It does appear to me that there's a big difference between what 
I see for the RPi4 and RPi3B+ at
Could someone verify that the dts/dtb for the RPi3B+ is/should be correct?
The last commit is from 2020-02-27 about power leds and the one before that is 
from 2019-08-15 and is about HDMI. But afaik, that was way before kernel 5.10 
was released. I do also see a 'hdmi' block in 'bcm2835-common.dtsi' so maybe 
it's all good, but I lack the knowledge to verify that.

> > I'll (soon) try the .libreelec file (renamed/linked ofc).

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
                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"
                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
                hdmi-output-0: HDMI / DisplayPort (type: HDMI, priority: 5900, latency offset: 0 usec, availability unknown)
                                device.icon_name = "video-display"
                       = "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.

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