[pulseaudio-discuss] Why no 'default device' option?

[Lennart Poettering]

On Wed, 25.11.09 13:37, Jeremy Nickurak (jeremy at nickurak.ca) wrote:

> On Wed, Nov 25, 2009 at 11:48, Colin Guthrie <gmane at colin.guthr.ie> wrote:
> 
> > PA will always remember what your app has chosen. So if you play something
> > with an app for the very first time, it is assigned to the fallback device
> > (we know no better).
> >
> 
> Is this the case even if you don't manually select one? Ie, the first time
> it's used, it uses the "fallback" device. The second time, does it still go
> to the "fallback", or does it go to the same device it "fell-back" to last
> time?
> 
> I'm hoping it's the former, in which case... what is the difference between
> a fall-back device and a default-device?

The former.

The logic is basically this:

If you never configured a particular device for a stream the device
selection will always be fully automatic until you configure one. If
you do not configure one recent PA versions even try to be smart when
selecting a device and move telephony streams automatically to
telephony headsets and so on.

However, if you ever configured a particular device for a stream this
configuration will be used if possible. "if possible" means that the
device needs to be available (plugged in) of course. If the
configuration is "not possible" we will revert to the same automatic
device selection as described above, but the configuration will be
kept, and later reevaluated when the configuration might suddenly
become "possible" again, due to hotplug.

That means: if the user configured something this takes absolute
precedence and will never be overriden, unless it cannot be fulfilled,
in which case we only override it temporarily and try to fulfill it as
soon as it is possible again. We never rewrite the configuration on
disk unless the user triggered it.

Hope this clears things up.

What I plan to add later on is that we keep a LRU list of configured
devices for a stream, instead of just one. 

Lennart

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