[alsa-devel] [pulseaudio-discuss] Problem with timing and USB scanning...

[Raymond Yau]

> > > Howdy! I have a situation where PulseAudio is "grabbing" a usb headset
> >
> > before
> >
> > > fully initialized, thus not all features are being recognized.
> >
> > > More details here:
> >
https://askubuntu.com/questions/537166/usb%2daudio%2ddevice%2dnot%2dfully%2d
> > working%2dafter%2dhotplug
> >
> > You have to post output of alsa-info.sh and pactl list before and after
the
> > hot plug
>
> This does not have my web cam attached.
>
> Files attached. I also did a pulse restart, and captured the pactl list
output
> after that too.
>
> > This look like priority issue if you have usb web cam mic and hotplug
usb
> > headset
> >
> >
>
https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/usb/mixer.c?id=9fcd0ab130579d9742538340edda3225f2b49a3e
>
> This happens even without the USB web cam plugged in.
>
> > Another issue is some usb devices only obtained dB scale at a later time
> > after the control is created
> >
> > This may need some delay for pulseaudio to get dB scale
> >
> > You can add printk statement to find out how much time you need
>
> I've done zero kernel hacking, so can't really help there, sorry!
>

Unfotunately, you need to fix many things in kernel

Is this a notebook with internal 5.1 speakers with three jacks at rear
panel (headphone , mic and line in) ?

1) large volume range of mic capture
Volume and speaker playback volume

https://git.kernel.org/cgit/linux/kernel/git/tiwai/sound.git/commit/sound/usb/mixer.c?id=9b4ef97757953c6071563b7cbfc689e3dd771603

2) your 5.1 internal speaker have same priority