Igor Kovalenko authored Apr 16, 2021 and PulseAudio Marge Bot committed Apr 19, 2021

When fallback mapping is selected all subsequent profile sets containing
selected mapping are ignored. When there are only e.g. fallback input mappings
available, admitted profile set will only contain one profile with selected
first input fallback mapping and no outputs, and rest of profiles will only
contain outputs and no inputs. When there are only fallback input and output
mappings, there will be no profiles admitted at all.

Fix this by making sure that selected first fallback input or output mapping
is actually allowed to exist in all probed profile sets.

Note while this change allows selected fallback mappings to be found in duplex
configuraitons, probing fallbacks still can fail if there is more than one input
fallback and first one (selected) does not work in duplex configurations.

Part-of: <pulseaudio/pulseaudio!539>