Re: [gentoo-user] USB sound

[Mark Knecht]

On Tue, Apr 28, 2020 at 8:11 AM Peter Humphrey <peter@××××××××××××.uk>
wrote:
>
> On Tuesday, 28 April 2020 15:21:09 BST Mark Knecht wrote:
> > On Tue, Apr 28, 2020 at 6:51 AM Peter Humphrey <peter@××××××××××××.uk>
>
> --->8
>
> > OK, so card 0 is using snd_hda_intel. Card 0 is most likely the default
> > location that sound is going. Blacklisting it will help. That said you
have
> > 2 USB devices so we need to be careful about extra confusion there. For
> > simplicity you might just unplug the webcam (if you can - if this is a
> > built-in in a laptop then I understand you have limitations.)
>
> --->8
>
> > > Nope. No pulseaudio.
> >
> > What is the output of pulseaudio at the command line?
>
> Not found.
>
> > Or maybe just no pluseaudio tools, or whatever it's called on Gentoo
> > assuming it's a separate package. I'm no longer running Gentoo (I just
find
> > this list the best place to get real info) A quick google for
pavucontrol
> > suggests you can emerge media-sound/pavucontrol to get it.
>
> Do I need it? I have sound without it. To install it I'd have to set the
> pulseaudio USE flag; then emerge -uaDvN @world would reinstall 19
packages and
> install 10 new ones.
>

Ah, so now we have more clues about what's going on. KDE supplies
pulseaudio. AFAIK it's part of the KDE installation on other distros. I'm
running Kubuntu LTS, not Gentoo, so I have pulseaudio because it's what the
Kubuntu guys give me. You have a USE flag that __YOU__ took responsibility
for turning off. (I'm not clear from this discussion what packages have a
pulseaudio flag - multiple packages I assume?

</SNARK> I have no idea whether rebuilding 19 packages and installing 10
new ones is a big deal for your system, nor can I say what the impact of
those changes would be to the way your system operates, but you're a Gentoo
guys so you must (!! ;) !!)) love building packages and experiments, right?
;-) (It's why I gave up using Gentoo for my desktop computers. I don't like
experiments so much anymore!)


> > Use KDE systemsettings, search for sound, choose 'Multimedia', Under
'Audio
> > Volume' what do you see? What device is set as default? (This part of
> > systemsettings is very similar to pavucontrol but it doesn't give you
the
> > VU meters which are nicely visible to see what apps are generating
audio.
>
> KDE system settings have changed since your day, Mark; there's now no
> reference to the hardware at all under Multimedia; only CDDB. There's no
> useful USE flag on it.
>

Or your choice to disable USE flags has removed some of the 'features' of
KDE. Again, I'm using completely updated stable Kubuntu LTS for my
day-to-day systems so there are clearly differences. However I suggest here
that the reason there is no multimedia under audio in system settings may
be because you haven't included the pulseaudio USE flag.

And I do understand that pulseaudio is sort of like Joan Jett singing Bad
Reputation. Joan, pulseaudio and by extension Mr. Pottering pretty much
'just don't care about my bad reputation'.

> --->8
>
> > > Third, I haven't any alsa packages installed, except for alsamixer
which I
> > > installed to help with this problem (it didn't). There's no starting
or
> > > stopping alsa; KDE seems to have what it needs without alsa
specifically.
> > > That's why I had no asound.conf; it's also why I rebooted instead of
doing
> > > something less heavy handed. Then again, why do I need an asound.conf?
> >
> > No. The fact that you can cat "/proc/asound" asound being "Alsa Sound"
says
> > Alsa is running. Alsa talks to your sound card hardware and provides a
> > "single application" interface to the sound cards. Pulseaudio provides a
> > mixer so that multiple apps can all send sound to your hardware.
>
> To clarify:
> prh@peak ~ $ eix -Ic alsa
> [I] media-libs/alsa-lib (1.2.2{tbz2}@22/04/20): Advanced Linux Sound
> Architecture Library
> prh@peak ~ $ eix -Ic audio
> [I] media-libs/audiofile (0.3.6-r3(0/1){tbz2}@11/04/20): An elegant API
for
> accessing audio files
>
> I can already send sound from several apps at once to the hardware - at
least,
> I could with the built-in Intel hardware. Time will tell how the USB
device
> fares. I think KDE must use media-libs/alsa-lib directly. It must be
doing a
> lot of work under the bonnet.
>

If Alsa under the hood is doing everything you need then let's drop the
pulseaudio part. pulseaudio is conceptually just a mixer.

> > I personally don't think you need asound.conf until you prove that you
have
> > a need to do some sort of non-standard configuration. That _might_ be
> > defining a different default card but KDE can do that for you in system
> > settings so my recommendation is no asound.conf for now. Use KDE as it's
> > intended and (over the long run) I think it's more maintainable.
However,
> > you are completely free to use your system any way you want.
>
> Thanks for your help.
>

Not sure I've helped so far. Sorry!

Have you blacklisted the snd_hda_intel driver, at least as a test? If so,
do you only see the USB card and the snd_usb_driver in /proc/asound? If so
do you have sound from the USB device?

I have nothing against creating an asound.conf file, if you want to, but I
don't have any recent experience with doing that. However it should allow
you to set your USB device as default if it's done correctly but in this
test configuration with blacklisted snd_hda_intel drivers I don't think
it's necessary and cannot see how it improves anything yet.

Mark