[pulseaudio-discuss] [RFC PATCH 0/4] Audio routing fixes and improvements

[João Paulo Rechi Vita]

These are patches we have been carrying downstream for quite some time
now at Endless (some of them which are a refactor of an earlier work by
Mario Sanchez Prada from ~3.5 years ago), plus a fix for problem I have
worked at recently (patches 3 and 4).

Essentially we want to have active streams (and default sink/source
configuration) moved to new devices on hotplug, but respecting a
priority list. My understanding is that this also what
module-device-manager provides, but it relies on something (a client?)
registering the priority lists, which on Colin's main target scenario
was kmix/phonon (although I must confess I have not looked too deeply
into m-d-m, so some of this may not be super accurate). We don't have
such piece to register priority lists at Endless, which uses the default
GNOME audio UI, and for this simpler, static case, a few changes on
module-switch-on-port-available (patches 1 and 2 of this series) have
been enough. The priorities come from the ALSA paths configuration
files, which we also tweaked a bit to fit our needs (not part of this
series).

In addition to what I mentioned on the previous paragraph, we also want
to have the same functionality working across different cards,
specifically for some laptops with AMD graphics, where all analog ports
are on one ALSA card but the HDMI port is on a separate ALSA card which
only has that port. With the recent default sink / source logic
improvements (thanks Tanu!) we can now have it working through
module-switch-on-connect, as long as we change it to not ignore HDMI
sinks (patch 4). But when testing this case I stumbled upon a problem
where a card can get stuck on an unavailable profile when there is no
other port to switch to, with a non-working sink available, which I'm
addressing with patch 3.

I believe all of these would be beneficial upstream and none of them are
too controversial, thus this series, but I'm open for any suggestions on
other possible approaches to address these problems and to do some
rework to have them suit upstream better.

Thanks in advance for any support.

João Paulo Rechi Vita (4):
  card: New API pa_card_profile_has_available_ports
  switch-on-port-available: Change criteria for keeping the active
    profile
  alsa-card: Switch profile when the active one becomes unavailable
  switch-on-connect: Do not ignore HDMI sinks

 src/modules/alsa/module-alsa-card.c           | 54 +++++++++++++++++++
 src/modules/module-switch-on-connect.c        | 13 +++--
 src/modules/module-switch-on-port-available.c | 32 +++++------
 src/pulsecore/card.c                          | 18 +++++++
 src/pulsecore/card.h                          |  3 ++
 5 files changed, 95 insertions(+), 25 deletions(-)

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2.18.0