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 is needed to update the GUI (mixer-strip I/O buttons)
when the engine is re-started with different I/O.
When Port::reconnect() cannot re-connect the port (e.g.
because the corresponding hardware port is missing), the IO object
needs o be notified -> PostDisconnect() -> IO::disconnect_check.
While the port-manager re-establishes and re-connects port,
port_manager->running() == false, and Port::get_connections()
returns the Port::_connections set (not actual engine connections).
So _connections.clear() has to be called synchronize it with
the actual engine connection state.
Previously it was possible to open the multiple IOSelectorWindows
from multiple locations: editor-mixer, mixer, track/bus inspector,
track header context menu, etc. for the same port.
A Pango::Layout created by Gtk::Widget::get_pango_context ()
does not have any font set. The Font is inherited from the
layout's context.
The actual font is set when the layout is used in
on_expose_event() via get_window ()->create_cairo_context ().
In some cases we rely on the font-size to calculate the widget's
size before rendering. At this point in time there is no drawing
context from which to inherit the style.
Furthermore, even after a call to `ensure_style()` in the c'tor
of a Widget get_font() simply returns the default value.
All Widgets that rely an Pango::Layout font size during
size-requests have to explicitly set the font.
This fixes various overlarge buttons with the initial default layout.
bind.hpp:36:1: note: ‘#pragma message: The practice of declaring the
Bind placeholders (_1, _2, ...) in the global namespace is deprecated.
Please use <boost/bind/bind.hpp> + using namespace boost::placeholders,
or define BOOST_BIND_GLOBAL_PLACEHOLDERS to retain the current behavior.
This allows to re-use playlist editing in all RouteUI derivatives,
not just the main editor time axis header.
The change is mostly a NO-OP, simply moving methods from
RouteTimeAxisView (is-a RouteUI), to RouteUI.
