[pulseaudio-discuss] Add a way to override priority of sinks - mostly for module-combine-sinks

[Myst Fox]

This is a bit hard to describe. I'd really like to see a way to manually
set priorities on sinks. I recently got a portable DAC, and I wanted to
use it when plugged in and fall back on module-combine-sink otherwise -
mostly because I often use a program that cannot handle changing sinks.
This however means I needed my priorities to be correctly ordered. After
fixing the identification of my DAC on the udev side, and switching to
running a git build to have recent fixes like
https://bugs.freedesktop.org/show_bug.cgi?id=99222, I ran into that I
wanted the module-combine-sink sink to be above my internal card but
below my DAC. I solved this for now with `load-module
module-combine-sink sink_properties='device.class="sound"
device.form_factor="speaker"'
`, but that's faking out the priority setting to get the right order,
not doing it any sort of "right".

I'm imagining adding a proplist entry of some naming that lets you
outright set the priority, and there would be a check at the start of
pa_device_init_priority in sink.c that would outright set the priority
if it was a valid value. I'd like to know, though, how that sounds, what
people think, ideas about the name, if there's anything big I might be
missing, before I try to work on a patch.

Sorry for duplication - I posted this as a bug,
https://bugs.freedesktop.org/show_bug.cgi?id=101201, but I realized
right after doing so that this mailing list is probably the
correct/better place to do so.

-- 
  Myst Fox
  myst at focks.pw