Re: [PATCH 5/6] audio/jack: honour the enable state of the audio device

[Geoffrey McRae]

On 2020-06-19 19:29, Gerd Hoffmann wrote:
> Hi,
>
> > > Hmm, I guess feeding silence into jack needs some cpu cycles?
> > > Maybe add a timer to close the jack server connection?  Keep the
> > > connection open for re-use for a while, but in case the guest stops
> > > playing sound altogether close the jack connection after being unused
> > > for a few minutes?
> > >
> > > [ Doesn't render the patch invalid, consider it a suggestion for future
> > >   improvements ]
> >
> > Thanks, I had considered that however there is a usability issue to
> > consider. Each time a jack client registers, it removes the client 
> > entirely
> > and disconnects any custom plumbing that may have been done by the 
> > user.
>
> Hmm, ok, that is bad indeed.
>
> Can you stop the stream without closing the connection?

Not as far as I can tell, it seems the JACK API doesn't allow for this 
in a way that is useful to us.

> > JACK does not remember this custom routing and as such it's lost until 
> > the
> > user re-establishes it, or they have some automation set up to do it. 
> > While
> > this could likely be worked around, it would likely cause more 
> > headaches
> > then the few CPU cycles lost in a memset.
>
> I'm more concerned about the frequent wakeups to feed the next chunk of
> (silence) data to jack.
>
> take care,
>   Gerd