From 82ce05ad017e8b074bbe9d67178293839b74f70a Mon Sep 17 00:00:00 2001 From: "Ryan C. Gordon" Date: Thu, 27 Jul 2023 18:22:20 -0400 Subject: [PATCH] pulseaudio: Be more aggressive with hotplug thread synchronization. (Borrowed from the SDL2 branch.) --- src/audio/pulseaudio/SDL_pulseaudio.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/src/audio/pulseaudio/SDL_pulseaudio.c b/src/audio/pulseaudio/SDL_pulseaudio.c index 5644802c9..fb6c35182 100644 --- a/src/audio/pulseaudio/SDL_pulseaudio.c +++ b/src/audio/pulseaudio/SDL_pulseaudio.c @@ -847,28 +847,47 @@ static int SDLCALL HotplugThread(void *data) { uint32_t prev_default_sink_index = default_sink_index; uint32_t prev_default_source_index = default_source_index; + pa_operation *op; SDL_SetThreadPriority(SDL_THREAD_PRIORITY_LOW); PULSEAUDIO_pa_threaded_mainloop_lock(pulseaudio_threaded_mainloop); PULSEAUDIO_pa_context_set_subscribe_callback(pulseaudio_context, HotplugCallback, NULL); - PULSEAUDIO_pa_operation_unref(PULSEAUDIO_pa_context_subscribe(pulseaudio_context, PA_SUBSCRIPTION_MASK_SINK | PA_SUBSCRIPTION_MASK_SOURCE | PA_SUBSCRIPTION_MASK_SERVER, NULL, NULL)); + + /* don't WaitForPulseOperation on the subscription; when it's done we'll be able to get hotplug events, but waiting doesn't changing anything. */ + op = PULSEAUDIO_pa_context_subscribe(pulseaudio_context, PA_SUBSCRIPTION_MASK_SINK | PA_SUBSCRIPTION_MASK_SOURCE | PA_SUBSCRIPTION_MASK_SERVER, NULL, NULL); + + SDL_PostSemaphore((SDL_Semaphore *) data); + while (SDL_AtomicGet(&pulseaudio_hotplug_thread_active)) { PULSEAUDIO_pa_threaded_mainloop_wait(pulseaudio_threaded_mainloop); + if (op && PULSEAUDIO_pa_operation_get_state(op) != PA_OPERATION_RUNNING) { + PULSEAUDIO_pa_operation_unref(op); + op = NULL; + } // Update default devices; don't hold the pulse lock during this, since it could deadlock vs a playing device that we're about to lock here. PULSEAUDIO_pa_threaded_mainloop_unlock(pulseaudio_threaded_mainloop); CheckDefaultDevice(&prev_default_sink_index, default_sink_index); CheckDefaultDevice(&prev_default_source_index, default_source_index); PULSEAUDIO_pa_threaded_mainloop_lock(pulseaudio_threaded_mainloop); + } - PULSEAUDIO_pa_context_set_subscribe_callback(pulseaudio_context, NULL, NULL); // Don't fire HotplugCallback again. + if (op) { + PULSEAUDIO_pa_operation_unref(op); + } + + PULSEAUDIO_pa_context_set_subscribe_callback(pulseaudio_context, NULL, NULL); PULSEAUDIO_pa_threaded_mainloop_unlock(pulseaudio_threaded_mainloop); return 0; + + } static void PULSEAUDIO_DetectDevices(SDL_AudioDevice **default_output, SDL_AudioDevice **default_capture) { + SDL_Semaphore *ready_sem = SDL_CreateSemaphore(0); + PULSEAUDIO_pa_threaded_mainloop_lock(pulseaudio_threaded_mainloop); WaitForPulseOperation(PULSEAUDIO_pa_context_get_server_info(pulseaudio_context, ServerInfoCallback, NULL)); WaitForPulseOperation(PULSEAUDIO_pa_context_get_sink_info_list(pulseaudio_context, SinkInfoCallback, (void *)((intptr_t)SDL_TRUE))); @@ -888,7 +907,9 @@ static void PULSEAUDIO_DetectDevices(SDL_AudioDevice **default_output, SDL_Audio /* ok, we have a sane list, let's set up hotplug notifications now... */ SDL_AtomicSet(&pulseaudio_hotplug_thread_active, 1); - pulseaudio_hotplug_thread = SDL_CreateThreadInternal(HotplugThread, "PulseHotplug", 256 * 1024, NULL); /* !!! FIXME: this can probably survive in significantly less stack space. */ + pulseaudio_hotplug_thread = SDL_CreateThreadInternal(HotplugThread, "PulseHotplug", 256 * 1024, ready_sem); // !!! FIXME: this can probably survive in significantly less stack space. + SDL_WaitSemaphore(ready_sem); + SDL_DestroySemaphore(ready_sem); } static void PULSEAUDIO_Deinitialize(void)