PortAudio uses what it calls 'default suggested latencies' but in callback streaming mode, they can result in wildly inaccurate buffer sizing (e.g. the user requests a buffer size of 128 but PortAudio actually instructs ASIO to use a much bigger size).
What we do now is to improve PortAudio's suggested latency calculation by basing it on the actual buffer size requested by the user.
The backend holds `_port_callback_mutex` while disconnecting ports.
In some cases disconnecting a port can drop the last reference
resulting in a port-deletion from the connection handler.
This in turn will eventually aquire the `_port_callback_mutex`
and deadlock.
This is now circumvented by using atomic operations instead of
taking a lock to set the `_port_change_flag`.
The flag is also used to trigger a latency update in some cases,
atomic is preferable to taking a lock to set this flag.
--
Full bt: https://paste.debian.net/1184056/
Short:
#1 in pthread_mutex_lock ()
#2 in ARDOUR::PortEngineSharedImpl::port_connect_add_remove_callback()
#3 in ARDOUR::BackendPort::~BackendPort()
#4 in ARDOUR::DummyPort::~DummyPort()
#6 in ARDOUR::DummyAudioPort::~DummyAudioPort()
#7 in boost::checked_delete<ARDOUR::BackendPort>(ARDOUR::BackendPort*)
#12 in boost::shared_ptr<ARDOUR::ProtoPort>::reset()
#13 in ARDOUR::Port::drop()
#14 in ARDOUR::Port::~Port()
#15 in ARDOUR::AudioPort::~AudioPort()
#17 in ARDOUR::AudioEngine::add_pending_port_deletion(ARDOUR::Port*)
#20 in boost::detail::sp_counted_base::release()
#37 in ARDOUR::PortManager::connect_callback() at libs/ardour/port_manager.cc:788
#38 in ARDOUR::DummyAudioBackend::main_process_thread() at libs/backends/dummy/dummy_audiobackend.cc:1018
This allow to restore original engine port-names as set
by the backend. ALSA MIDI, CoreAudio, CoreMIDI and PortAudio
drivers can provide human readable physical port names for
some devices.
gcc can recognize various regexps in comments. Since C++17 provides
[[fallthrough]], using /* fallthrough */ consistently seems
appropriate until we switch to C++17.
see also https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html
* PortEngine::available() implementation
* AudioEngine::connected() wrapper
Eventually we may re-introduce PortEngine::available along
with a libardour internal port-engine.
Set accumulated capture-latency for physical-outputs
and accumulated playback-latency for physical-inputs
after Ardour is done setting all non-physical port latencies.
This will be needed for latency-compensation of the complete graph.
Generated by tools/f2s. Some hand-editing will be required in a few places to fix up comments related to timecode
and video in order to keep the legible
pthread-w32 does not support pthread_setschedparam() with
SCHED_FIFO and bails out. While pthread_create() simply ignores the policy
and sets the priority regadless.
This only affects ctrl-surface event-loops & AutomationWatch on Windows.
This hopefully fixes an issue with port-registration (new session)
being skipped because PortAudioBackend::available() still false
until the first callback.
This issue is not always reproducible but when it does occur it happens
somewhat consistently on both 32bit and 64bit builds(Tested on Windows 7).
The midiOutReset call does not return (or it takes so long that it might as
well be indefinite) and as it is not strictly necessary just remove it.
Resolves: http://tracker.ardour.org/view.php?id=7095
