Hui Wang authored May 15, 2019 and Tanu Kaskinen committed Jun 09, 2019

We met two problems recently, one happened on a Lenovo machine with
dual analogue codecs, the other happened on a Dell machine with
a digital mic directly connected to PCH. The two problems are
basically same, there is an internal mic and an external mic, the
internal mic always shows up in the gnome-control-center, the external
mic only shows up when it is plugged. After the external mic is
plugged and users select it from gnome-control-center, the
gnome-control-center will read all saved streams through extension_cb,
and bind the source of external mic to all streams, after that the
apps only record sound via the source of external mic, after the
external mic is unplugged, the internal mic will automatically be
selected since it is the only left input device in the
gnome-control-center, since users don't select it, all streams are
still bond the source of external mic. When users record sound via
apps, they can't record any sound even the default_source is the
source of internal mic and the internal mic is selected in the UI.

It is very common that a machine has internal mic and external mic,
but this problem didn't expose before, that is because both internal
mic and external mic belong to one source, but for those two
machines, the internal mic belongs to one source, while the external
mic belongs to another source (they are in differnt codecs or one is
in the codec and the other is from PCH),

To fix it with a mininal change, we just check if the active_port is
PA_AVAILABLE_NO or not when building a new stream, if it is, don't
restore the device to the new built stream, let pa_source_output_new()
decide the source device for this stream.

And we also do the same change to sink_input.

This change only affects the new built streams, it will not change
the database, so the users' preference is still saved in the database,
after the active_port is not PA_AVAILABLE_NO, the new streams will
still restore to the preferred device.

Signed-off-by: Hui Wang <hui.wang@canonical.com>