[pulseaudio-discuss] Automatic selection of an audio sink depending on value of ENV variable

Lennart Poettering lennart at poettering.net
Mon Oct 26 08:05:44 PDT 2009

On Mon, 26.10.09 15:03, Leszek Koltunski (leszek at koltunski.pl) wrote:

> > We can do this, Not sure it makes a lot of sense though in the general
> > case, and makes we wonder how long before someone wants to attach this
> > informaton to a monitor, not a screen or display.
> >
> > And then again, running a display with multiple screens is kinda
> > exotic in my eyes. The more common case is to have one screen with
> > multiple monitors. And that's what we should optimize for.
> >
> > I'll try to argue with the above.
> If one runs NVidia proprietary drivers ( last time I used ATI - ~3ys ago -
> it was the same over there ) and wants to connect more than one monitor,
> NVidia offers two ways to do it: you can setup the second monitor to be what
> they call a "separate X screen" ( and that it precisely what I have here )
> or a "TwinView" (nvidia-speak for Xinerama ).
> Now, the main difference between those two modes is this: Xinerama
> connects 2 or more monitors into one big desktop (gnome panels
> stretch across both monitors, one can drag windows between them etc

this is bogus. gnome-panel is xinerama-aware and does not stretch
panels across to monitors of the same screen.

> ) whereas 'separate X screen' creates 2 separate desktops (2 copies
> of gnome-panels appear, one on each monitor, dragging is impossible,
> each monitor has its own icons, trays etc ) .

Yepp, and I'd argue the non-xinerama setup is useless.

> That means that if one chooses Xinerama, most probably his monitors are
> located physically next to each other. But in this case he likely does NOT
> need a separate sound sink for each monitor! If however one goes for
> 'separate X screen' , then he most probably wants some kind of a multiseat
> setup, or maybe - like in my case - his monitors are far away from each
> other. In precisely this case people tend to need separate sound
> sinks.

I don't think that makes sense. Proper Multiseat means seperate
authorization for both screens of your display, but X does not offer
you that.

> Current strategy of attaching an X prop to a display gives this flexibility
> only to those who are knowledgeable enough to set this up manually in
> xorg.conf; NVidia and ATI graphical tools cannot do it.

Uh? the xinerama stuff is what we support just fine.

> Attaching X prop to a screen would give this flexibility to 'dual screen'
> users, and those actually tend to need it.

I don't think this is a realistic use-case. It's very much fabricated.

> Going for 'seperate sound sink for each monitor' first of all would require
> a radical redesign of Pulse, and second would not result in much additional
> benefit ( only Xinerama people would potentially gain, but those do not need
> this functionality anyway )

Radical redesign? Certainly not.

I am not sure I sufficiently made the clear what the differences displays,
screens, and monitors after all are.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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