From ca6e6c866b250dac68d25c0d75d241afe6b42284 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Mon, 15 Sep 2025 15:23:26 +0200
Subject: [PATCH 01/22] Add a waiting state

Also fix erroneous looking switch fall-through.
---
 test/webaudio/audioworklet_emscripten_locks.c | 24 +++++++++----------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 20471eced5f63..7482f0bab7ff5 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -17,6 +17,8 @@
 int _emscripten_thread_supports_atomics_wait(void);
 
 typedef enum {
+  // The test hasn't yet started
+  TEST_NOT_STARTED,
   // No wait support in audio worklets
   TEST_HAS_WAIT,
   // Acquired in main, fail in process
@@ -40,26 +42,17 @@ typedef enum {
 // Lock used in all the tests
 emscripten_lock_t testLock = EMSCRIPTEN_LOCK_T_STATIC_INITIALIZER;
 // Which test is running (sometimes in the worklet, sometimes in the main thread)
-_Atomic Test whichTest = TEST_HAS_WAIT;
+_Atomic Test whichTest = TEST_NOT_STARTED;
 // Time at which the test starts taken in main()
 double startTime = 0;
 
 bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs, AudioSampleFrame *outputs, int numParams, const AudioParamFrame *params, void *userData) {
   assert(emscripten_current_thread_is_audio_worklet());
 
-  // Produce at few empty frames of audio before we start trying to interact
-  // with the with main thread.
-  // On chrome at least it appears the main thread completely blocks until
-  // a few frames have been produced.  This means it may not be safe to interact
-  // with the main thread during initial frames?
-  // In my experiments it seems like 5 was the magic number that I needed to
-  // produce before the main thread could continue to run.
-  // See https://github.com/emscripten-core/emscripten/issues/24213
-  static int count = 0;
-  if (count++ < 5) return true;
-
   int result = 0;
   switch (whichTest) {
+  case TEST_NOT_STARTED:
+    break;
   case TEST_HAS_WAIT:
     // Should not have wait support here
     result = _emscripten_thread_supports_atomics_wait();
@@ -80,6 +73,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     emscripten_outf("TEST_WAIT_ACQUIRE_FAIL: %d (expect: 0)", result);
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE;
+    break;
   case TEST_WAIT_ACQUIRE:
     // Will get unlocked in main thread, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 10000);
@@ -130,6 +124,10 @@ bool MainLoop(double time, void* data) {
   assert(!emscripten_current_thread_is_audio_worklet());
   static int didUnlock = false;
   switch (whichTest) {
+  case TEST_NOT_STARTED:
+    emscripten_out("Staring test (may need a button click)");
+    whichTest = TEST_HAS_WAIT;
+    break;
   case TEST_WAIT_ACQUIRE:
     if (!didUnlock) {
       emscripten_out("main thread releasing lock");
@@ -178,9 +176,9 @@ int main() {
 
   startTime = emscripten_get_now();
 
-  emscripten_set_timeout_loop(MainLoop, 10, NULL);
   EMSCRIPTEN_WEBAUDIO_T context = emscripten_create_audio_context(NULL);
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
+  emscripten_set_timeout_loop(MainLoop, 10, NULL);
 
   emscripten_exit_with_live_runtime();
 }

From 569db6dc5c5c07bb6dff573c224bd6c58b2dca30 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Mon, 15 Sep 2025 18:11:20 +0200
Subject: [PATCH 02/22] Move work off the main thread

---
 test/webaudio/audioworklet_emscripten_locks.c | 74 +++++++++++--------
 1 file changed, 43 insertions(+), 31 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 7482f0bab7ff5..fe84eb0fdfac7 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -46,6 +46,12 @@ _Atomic Test whichTest = TEST_NOT_STARTED;
 // Time at which the test starts taken in main()
 double startTime = 0;
 
+void do_exit() {
+  emscripten_out("Test success");
+  emscripten_terminate_all_wasm_workers();
+  emscripten_force_exit(0);
+}
+
 bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs, AudioSampleFrame *outputs, int numParams, const AudioParamFrame *params, void *userData) {
   assert(emscripten_current_thread_is_audio_worklet());
 
@@ -120,37 +126,39 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   };
 });
 
-bool MainLoop(double time, void* data) {
+void WorkerLoop() {
   assert(!emscripten_current_thread_is_audio_worklet());
-  static int didUnlock = false;
-  switch (whichTest) {
-  case TEST_NOT_STARTED:
-    emscripten_out("Staring test (may need a button click)");
-    whichTest = TEST_HAS_WAIT;
-    break;
-  case TEST_WAIT_ACQUIRE:
-    if (!didUnlock) {
-      emscripten_out("main thread releasing lock");
-      // Release here to acquire in process
-      emscripten_lock_release(&testLock);
-      didUnlock = true;
-    }
-    break;
-  case TEST_WAIT_INFINTE_1:
-    // Spin here until released in process (but don't change test until we know this case ran)
-    whichTest = TEST_WAIT_INFINTE_2;
-    emscripten_lock_busyspin_waitinf_acquire(&testLock);
-    emscripten_out("TEST_WAIT_INFINTE (from main)");
-    break;
-  case TEST_DONE:
-    // Finished, exit from the main thread
-    emscripten_out("Test success");
-    emscripten_force_exit(0);
-    return false;
-  default:
-    break;
+  int didUnlock = false;
+  while (true) {
+	  switch (whichTest) {
+	  case TEST_NOT_STARTED:
+		emscripten_out("Staring test (may need a button click)");
+		whichTest = TEST_HAS_WAIT;
+		break;
+	  case TEST_WAIT_ACQUIRE:
+		if (!didUnlock) {
+		  emscripten_out("main thread releasing lock");
+		  // Release here to acquire in process
+		  emscripten_lock_release(&testLock);
+		  didUnlock = true;
+		}
+		break;
+	  case TEST_WAIT_INFINTE_1:
+		// Spin here until released in process (but don't change test until we know this case ran)
+		whichTest = TEST_WAIT_INFINTE_2;
+		emscripten_lock_busyspin_waitinf_acquire(&testLock);
+		emscripten_out("TEST_WAIT_INFINTE (from main)");
+		break;
+	  case TEST_DONE:
+		// Finished, exit from the main thread (and return out of this loop)
+		emscripten_wasm_worker_post_function_v(EMSCRIPTEN_WASM_WORKER_ID_PARENT, &do_exit);
+		return;
+	  default:
+		break;
+	  }
+	  // Repeat every 16ms (except when TEST_DONE)
+	  emscripten_wasm_worker_sleep(16 * 1000000ULL);
   }
-  return true;
 }
 
 void AudioWorkletProcessorCreated(EMSCRIPTEN_WEBAUDIO_T audioContext, bool success, void *userData) {
@@ -169,16 +177,20 @@ void WebAudioWorkletThreadInitialized(EMSCRIPTEN_WEBAUDIO_T audioContext, bool s
 uint8_t wasmAudioWorkletStack[2048];
 
 int main() {
-  // Main thread init and acquire (work passes to the processor)
+  // Main thread init and acquire (work passes to the audio processor)
   emscripten_lock_init(&testLock);
   int hasLock = emscripten_lock_busyspin_wait_acquire(&testLock, 0);
   assert(hasLock);
 
   startTime = emscripten_get_now();
 
+  // Audio processor callback setup
   EMSCRIPTEN_WEBAUDIO_T context = emscripten_create_audio_context(NULL);
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
-  emscripten_set_timeout_loop(MainLoop, 10, NULL);
+  
+  // Worker thread setup
+  emscripten_wasm_worker_t worker = emscripten_malloc_wasm_worker(1024);
+  emscripten_wasm_worker_post_function_v(worker, WorkerLoop);
 
   emscripten_exit_with_live_runtime();
 }

From 1db640d9bf2f375d03e9c23e85f47aa6e8ec90ef Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Mon, 15 Sep 2025 18:13:55 +0200
Subject: [PATCH 03/22] Updated docs

---
 test/webaudio/audioworklet_emscripten_locks.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index fe84eb0fdfac7..6fa6a0ccc9832 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -41,7 +41,7 @@ typedef enum {
 
 // Lock used in all the tests
 emscripten_lock_t testLock = EMSCRIPTEN_LOCK_T_STATIC_INITIALIZER;
-// Which test is running (sometimes in the worklet, sometimes in the main thread)
+// Which test is running (sometimes in the worklet, sometimes in the worker)
 _Atomic Test whichTest = TEST_NOT_STARTED;
 // Time at which the test starts taken in main()
 double startTime = 0;
@@ -81,7 +81,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     whichTest = TEST_WAIT_ACQUIRE;
     break;
   case TEST_WAIT_ACQUIRE:
-    // Will get unlocked in main thread, so should quickly acquire
+    // Will get unlocked in worker, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 10000);
     emscripten_outf("TEST_WAIT_ACQUIRE: %d  (expect: 1)", result);
     assert(result);
@@ -96,7 +96,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     whichTest = TEST_WAIT_INFINTE_1;
     break;
   case TEST_WAIT_INFINTE_1:
-    // Still locked when we enter here but move on in the main thread
+    // Still locked when we enter here but move on in the worker
     break;
   case TEST_WAIT_INFINTE_2:
     emscripten_lock_release(&testLock);
@@ -137,7 +137,7 @@ void WorkerLoop() {
 		break;
 	  case TEST_WAIT_ACQUIRE:
 		if (!didUnlock) {
-		  emscripten_out("main thread releasing lock");
+		  emscripten_out("Worker releasing lock");
 		  // Release here to acquire in process
 		  emscripten_lock_release(&testLock);
 		  didUnlock = true;
@@ -147,7 +147,7 @@ void WorkerLoop() {
 		// Spin here until released in process (but don't change test until we know this case ran)
 		whichTest = TEST_WAIT_INFINTE_2;
 		emscripten_lock_busyspin_waitinf_acquire(&testLock);
-		emscripten_out("TEST_WAIT_INFINTE (from main)");
+		emscripten_out("TEST_WAIT_INFINTE (from worker)");
 		break;
 	  case TEST_DONE:
 		// Finished, exit from the main thread (and return out of this loop)

From d347a766e018b640b74bd01f4b7bd8a099e690b8 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Mon, 15 Sep 2025 19:16:32 +0200
Subject: [PATCH 04/22] Something to re-run the CI

---
 test/webaudio/audioworklet_emscripten_locks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 6fa6a0ccc9832..bd71bd302c917 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -19,7 +19,7 @@ int _emscripten_thread_supports_atomics_wait(void);
 typedef enum {
   // The test hasn't yet started
   TEST_NOT_STARTED,
-  // No wait support in audio worklets
+  // No atomics wait support in audio worklets
   TEST_HAS_WAIT,
   // Acquired in main, fail in process
   TEST_TRY_ACQUIRE,

From dda7d0550bda84844e84fc8968e9ef8d1f24ff00 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Tue, 16 Sep 2025 13:40:12 +0200
Subject: [PATCH 05/22] Added docs (and moved the a spin to happen faster)

---
 test/webaudio/audioworklet_emscripten_locks.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index bd71bd302c917..68a81bd08bc8d 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -79,7 +79,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     emscripten_outf("TEST_WAIT_ACQUIRE_FAIL: %d (expect: 0)", result);
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE;
-    break;
+    // Fall through here so the worker has a chance to unlock whilst spinning
   case TEST_WAIT_ACQUIRE:
     // Will get unlocked in worker, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 10000);
@@ -107,6 +107,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     emscripten_outf("TEST_GET_NOW: %d  (expect: > 0)", result);
     assert(result > 0);
     whichTest = TEST_DONE;
+    // Fall through here and stop playback (shutting down in the worker)
   case TEST_DONE:
     return false;
   default:

From 9a67852e257186fd4db8e59a6105254ca3378c25 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Tue, 16 Sep 2025 14:38:00 +0200
Subject: [PATCH 06/22] Removed flaky flag

---
 test/test_browser.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index 8c2d013a61040..f35cb078e198c 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5504,7 +5504,6 @@ def test_audio_worklet_params_mixing(self, args):
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
   @requires_sound_hardware
   @also_with_minimal_runtime
-  @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
   def test_audio_worklet_emscripten_locks(self):
     self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'])
 

From 52c6052e0c8d728187f67a0fad99a405f3061253 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Tue, 16 Sep 2025 14:43:16 +0200
Subject: [PATCH 07/22] Removed flaky import

---
 test/test_browser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index f35cb078e198c..7b8ace3fe3757 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -19,7 +19,7 @@
 
 import common
 from common import BrowserCore, RunnerCore, path_from_root, has_browser, Reporting, is_chrome, is_firefox, CHROMIUM_BASED_BROWSERS
-from common import create_file, parameterized, ensure_dir, disabled, flaky, test_file, WEBIDL_BINDER
+from common import create_file, parameterized, ensure_dir, disabled, test_file, WEBIDL_BINDER
 from common import read_file, EMRUN, no_wasm64, no_2gb, no_4gb, copytree
 from common import requires_wasm2js, parameterize, find_browser_test_file, with_all_sjlj
 from common import also_with_minimal_runtime, also_with_wasm2js, also_with_asan, also_with_wasmfs

From f19b38cd4547aa3470d9f9484e21b327087b8225 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Tue, 16 Sep 2025 16:00:36 +0200
Subject: [PATCH 08/22] Revert "Removed flaky import"

This reverts commit cdc1834070d6246974ffd59f188bfa24742d2f68.
---
 test/test_browser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index 7b8ace3fe3757..f35cb078e198c 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -19,7 +19,7 @@
 
 import common
 from common import BrowserCore, RunnerCore, path_from_root, has_browser, Reporting, is_chrome, is_firefox, CHROMIUM_BASED_BROWSERS
-from common import create_file, parameterized, ensure_dir, disabled, test_file, WEBIDL_BINDER
+from common import create_file, parameterized, ensure_dir, disabled, flaky, test_file, WEBIDL_BINDER
 from common import read_file, EMRUN, no_wasm64, no_2gb, no_4gb, copytree
 from common import requires_wasm2js, parameterize, find_browser_test_file, with_all_sjlj
 from common import also_with_minimal_runtime, also_with_wasm2js, also_with_asan, also_with_wasmfs

From 5983cda0fbfe4bd0310c3785b2c7f73916ac4b4f Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Tue, 16 Sep 2025 17:34:22 +0200
Subject: [PATCH 09/22] Revert "Removed flaky flag"

This reverts commit 4df7999cb32fc68a9d56aaee59376005d1db0f09.
---
 test/test_browser.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/test_browser.py b/test/test_browser.py
index f35cb078e198c..8c2d013a61040 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5504,6 +5504,7 @@ def test_audio_worklet_params_mixing(self, args):
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
   @requires_sound_hardware
   @also_with_minimal_runtime
+  @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
   def test_audio_worklet_emscripten_locks(self):
     self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'])
 

From 04cdeb03c90a95fa72499615501a002f880f46ba Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Fri, 19 Sep 2025 13:29:08 +0200
Subject: [PATCH 10/22] Added explicit audio shutdown

---
 test/webaudio/audioworklet_emscripten_locks.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 68a81bd08bc8d..1a2423ace578b 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -13,6 +13,9 @@
 // - emscripten_lock_release()
 // - emscripten_get_now()
 
+// Global audio context
+EMSCRIPTEN_WEBAUDIO_T context;
+
 // Internal, found in 'system/lib/pthread/threading_internal.h' (and requires building with -pthread)
 int _emscripten_thread_supports_atomics_wait(void);
 
@@ -48,6 +51,7 @@ double startTime = 0;
 
 void do_exit() {
   emscripten_out("Test success");
+  emscripten_destroy_audio_context(context);
   emscripten_terminate_all_wasm_workers();
   emscripten_force_exit(0);
 }
@@ -186,7 +190,8 @@ int main() {
   startTime = emscripten_get_now();
 
   // Audio processor callback setup
-  EMSCRIPTEN_WEBAUDIO_T context = emscripten_create_audio_context(NULL);
+  context = emscripten_create_audio_context(NULL);
+  assert(context);
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
   
   // Worker thread setup

From 82405f74aa3b5036f0e3fd0b81f2fe01d65ea12d Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Fri, 19 Sep 2025 14:45:54 +0200
Subject: [PATCH 11/22] Removed flaky (again)

---
 test/test_browser.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index 8c2d013a61040..f35cb078e198c 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5504,7 +5504,6 @@ def test_audio_worklet_params_mixing(self, args):
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
   @requires_sound_hardware
   @also_with_minimal_runtime
-  @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
   def test_audio_worklet_emscripten_locks(self):
     self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'])
 

From 42a582db7011eb5c68786e7d35441fc2a43a7ef9 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Mon, 10 Nov 2025 13:51:36 +0100
Subject: [PATCH 12/22] Re-added flaky

This reverts commit 82405f74aa3b5036f0e3fd0b81f2fe01d65ea12d.
---
 test/test_browser.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/test/test_browser.py b/test/test_browser.py
index 0b88db80c852a..18ca7709c7eb1 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5617,6 +5617,7 @@ def test_audio_worklet_params_mixing(self, args):
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
   @requires_sound_hardware
   @also_with_minimal_runtime
+  @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
   def test_audio_worklet_emscripten_locks(self):
     self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'])
 

From 76d750cb69f4b02e4446fd342ddfde1d25a485c3 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 14:01:32 +0100
Subject: [PATCH 13/22] Run on both main and worker thread

---
 test/test_browser.py                          | 10 ++--
 test/webaudio/audioworklet_emscripten_locks.c | 52 ++++++++++++++-----
 2 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index 18ca7709c7eb1..368e4f42acd4d 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5615,11 +5615,15 @@ def test_audio_worklet_params_mixing(self, args):
     self.btest_exit('webaudio/audioworklet_params_mixing.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-DTEST_AND_EXIT'] + args)
 
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
-  @requires_sound_hardware
   @also_with_minimal_runtime
+  @parameterized({
+    '': ([],),
+    'worker': (['-DTEST_ON_WORKER'],),
+  })
+  @requires_sound_hardware
   @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
-  def test_audio_worklet_emscripten_locks(self):
-    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'])
+  def test_audio_worklet_emscripten_locks(self, args):
+    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'] + args)
 
   # Verifies setting audio context sample rate, and that emscripten_audio_context_sample_rate() works.
   @requires_sound_hardware
diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 1a2423ace578b..14761244aef40 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -12,6 +12,8 @@
 // - emscripten_lock_busyspin_waitinf_acquire()
 // - emscripten_lock_release()
 // - emscripten_get_now()
+//
+// Define TEST_ON_WORKER to run on a worker, otherwise it runs on the main thread
 
 // Global audio context
 EMSCRIPTEN_WEBAUDIO_T context;
@@ -44,7 +46,7 @@ typedef enum {
 
 // Lock used in all the tests
 emscripten_lock_t testLock = EMSCRIPTEN_LOCK_T_STATIC_INITIALIZER;
-// Which test is running (sometimes in the worklet, sometimes in the worker)
+// Which test is running (sometimes in the worklet, sometimes in the worker/main)
 _Atomic Test whichTest = TEST_NOT_STARTED;
 // Time at which the test starts taken in main()
 double startTime = 0;
@@ -52,7 +54,9 @@ double startTime = 0;
 void do_exit() {
   emscripten_out("Test success");
   emscripten_destroy_audio_context(context);
+#ifdef TEST_ON_WORKER
   emscripten_terminate_all_wasm_workers();
+#endif
   emscripten_force_exit(0);
 }
 
@@ -83,9 +87,9 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     emscripten_outf("TEST_WAIT_ACQUIRE_FAIL: %d (expect: 0)", result);
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE;
-    // Fall through here so the worker has a chance to unlock whilst spinning
+    // Fall through here so the worker/main has a chance to unlock whilst spinning
   case TEST_WAIT_ACQUIRE:
-    // Will get unlocked in worker, so should quickly acquire
+    // Will get unlocked in worker/main, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 10000);
     emscripten_outf("TEST_WAIT_ACQUIRE: %d  (expect: 1)", result);
     assert(result);
@@ -100,7 +104,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     whichTest = TEST_WAIT_INFINTE_1;
     break;
   case TEST_WAIT_INFINTE_1:
-    // Still locked when we enter here but move on in the worker
+    // Still locked when we enter here but move on in the worker/main
     break;
   case TEST_WAIT_INFINTE_2:
     emscripten_lock_release(&testLock);
@@ -111,7 +115,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     emscripten_outf("TEST_GET_NOW: %d  (expect: > 0)", result);
     assert(result > 0);
     whichTest = TEST_DONE;
-    // Fall through here and stop playback (shutting down in the worker)
+    // Fall through here and stop playback (shutting down in the worker/main)
   case TEST_DONE:
     return false;
   default:
@@ -131,10 +135,16 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   };
 });
 
+#ifdef TEST_ON_WORKER
 void WorkerLoop() {
+#else
+bool MainLoop(double time, void* data) {
+#endif
   assert(!emscripten_current_thread_is_audio_worklet());
   int didUnlock = false;
+#ifdef TEST_ON_WORKER
   while (true) {
+#endif
 	  switch (whichTest) {
 	  case TEST_NOT_STARTED:
 		emscripten_out("Staring test (may need a button click)");
@@ -142,7 +152,7 @@ void WorkerLoop() {
 		break;
 	  case TEST_WAIT_ACQUIRE:
 		if (!didUnlock) {
-		  emscripten_out("Worker releasing lock");
+		  emscripten_out("Worker/main releasing lock");
 		  // Release here to acquire in process
 		  emscripten_lock_release(&testLock);
 		  didUnlock = true;
@@ -152,30 +162,42 @@ void WorkerLoop() {
 		// Spin here until released in process (but don't change test until we know this case ran)
 		whichTest = TEST_WAIT_INFINTE_2;
 		emscripten_lock_busyspin_waitinf_acquire(&testLock);
-		emscripten_out("TEST_WAIT_INFINTE (from worker)");
+		emscripten_out("TEST_WAIT_INFINTE (from worker/main)");
 		break;
 	  case TEST_DONE:
 		// Finished, exit from the main thread (and return out of this loop)
+#ifdef TEST_ON_WORKER
 		emscripten_wasm_worker_post_function_v(EMSCRIPTEN_WASM_WORKER_ID_PARENT, &do_exit);
+        // WorkerLoop contract (end the worker)
 		return;
+#else
+        do_exit();
+        // MainLoop contract (stop the repeats)
+        return false;
+#endif
 	  default:
 		break;
 	  }
-	  // Repeat every 16ms (except when TEST_DONE)
-	  emscripten_wasm_worker_sleep(16 * 1000000ULL);
+#ifdef TEST_ON_WORKER
+    // Repeat every 10ms (except when TEST_DONE)
+    emscripten_wasm_worker_sleep(10 * 1000000ULL);
   }
+#else
+    // Run again
+    return true;
+#endif
 }
 
 void AudioWorkletProcessorCreated(EMSCRIPTEN_WEBAUDIO_T audioContext, bool success, void *userData) {
   int outputChannelCounts[1] = { 1 };
   EmscriptenAudioWorkletNodeCreateOptions options = { .numberOfInputs = 0, .numberOfOutputs = 1, .outputChannelCounts = outputChannelCounts };
-  EMSCRIPTEN_AUDIO_WORKLET_NODE_T wasmAudioWorklet = emscripten_create_wasm_audio_worklet_node(audioContext, "noise-generator", &options, &ProcessAudio, NULL);
+  EMSCRIPTEN_AUDIO_WORKLET_NODE_T wasmAudioWorklet = emscripten_create_wasm_audio_worklet_node(audioContext, "locks-test", &options, &ProcessAudio, NULL);
   emscripten_audio_node_connect(wasmAudioWorklet, audioContext, 0, 0);
   InitHtmlUi(audioContext);
 }
 
 void WebAudioWorkletThreadInitialized(EMSCRIPTEN_WEBAUDIO_T audioContext, bool success, void *userData) {
-  WebAudioWorkletProcessorCreateOptions opts = { .name = "noise-generator" };
+  WebAudioWorkletProcessorCreateOptions opts = { .name = "locks-test" };
   emscripten_create_wasm_audio_worklet_processor_async(audioContext, &opts, AudioWorkletProcessorCreated, NULL);
 }
 
@@ -193,10 +215,14 @@ int main() {
   context = emscripten_create_audio_context(NULL);
   assert(context);
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
-  
-  // Worker thread setup
+
+  // Either call every 10ms or create a worker that sleeps every 10ms
+#ifdef TEST_ON_WORKER
   emscripten_wasm_worker_t worker = emscripten_malloc_wasm_worker(1024);
   emscripten_wasm_worker_post_function_v(worker, WorkerLoop);
+#else
+  emscripten_set_timeout_loop(MainLoop, 10, NULL);
+#endif
 
   emscripten_exit_with_live_runtime();
 }

From e2106bb9540679401243ed4a842e503ef1e1c41f Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 15:08:07 +0100
Subject: [PATCH 14/22] Allow out calls to be silenced

---
 test/webaudio/audioworklet_emscripten_locks.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 14761244aef40..f6cb57c92bb93 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -3,6 +3,8 @@
 #include <emscripten/webaudio.h>
 #include <assert.h>
 
+#define QUIET_AUDIO_WORKLET
+
 // Tests that these audio worklet compatible functions work, details in comments below:
 //
 // - _emscripten_thread_supports_atomics_wait()
@@ -70,28 +72,36 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
   case TEST_HAS_WAIT:
     // Should not have wait support here
     result = _emscripten_thread_supports_atomics_wait();
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_HAS_WAIT: %d (expect: 0)", result);
+#endif
     assert(!result);
     whichTest = TEST_TRY_ACQUIRE;
     break;
   case TEST_TRY_ACQUIRE:
     // Was locked after init, should fail to acquire
     result = emscripten_lock_try_acquire(&testLock);
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_TRY_ACQUIRE: %d (expect: 0)", result);
+#endif
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE_FAIL;
     break;
   case TEST_WAIT_ACQUIRE_FAIL:
     // Still locked so we fail to acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 100);
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_WAIT_ACQUIRE_FAIL: %d (expect: 0)", result);
+#endif
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE;
     // Fall through here so the worker/main has a chance to unlock whilst spinning
   case TEST_WAIT_ACQUIRE:
     // Will get unlocked in worker/main, so should quickly acquire
-    result = emscripten_lock_busyspin_wait_acquire(&testLock, 10000);
+    result = emscripten_lock_busyspin_wait_acquire(&testLock, 1000);
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_WAIT_ACQUIRE: %d  (expect: 1)", result);
+#endif
     assert(result);
     whichTest = TEST_RELEASE;
     break;
@@ -99,7 +109,9 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     // Unlock, check the result
     emscripten_lock_release(&testLock);
     result = emscripten_lock_try_acquire(&testLock);
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_RELEASE: %d (expect: 1)", result);
+#endif
     assert(result);
     whichTest = TEST_WAIT_INFINTE_1;
     break;
@@ -112,7 +124,9 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     break;
   case TEST_GET_NOW:
     result = (int) (emscripten_get_now() - startTime);
+#ifndef QUIET_AUDIO_WORKLET
     emscripten_outf("TEST_GET_NOW: %d  (expect: > 0)", result);
+#endif
     assert(result > 0);
     whichTest = TEST_DONE;
     // Fall through here and stop playback (shutting down in the worker/main)

From db0c8aa6480468e4ff6bb9ae3905de8a92dfb34f Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 15:30:56 +0100
Subject: [PATCH 15/22] Only run on worker, re-enable out() calls

---
 test/test_browser.py                          | 10 +++-------
 test/webaudio/audioworklet_emscripten_locks.c |  3 +--
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index 368e4f42acd4d..f563bebea4c4a 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5615,15 +5615,11 @@ def test_audio_worklet_params_mixing(self, args):
     self.btest_exit('webaudio/audioworklet_params_mixing.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-DTEST_AND_EXIT'] + args)
 
   # Tests AudioWorklet with emscripten_lock_busyspin_wait_acquire() and friends
-  @also_with_minimal_runtime
-  @parameterized({
-    '': ([],),
-    'worker': (['-DTEST_ON_WORKER'],),
-  })
   @requires_sound_hardware
+  @also_with_minimal_runtime
   @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
-  def test_audio_worklet_emscripten_locks(self, args):
-    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread'] + args)
+  def test_audio_worklet_emscripten_locks(self):
+    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread', '-DTEST_ON_WORKER'])
 
   # Verifies setting audio context sample rate, and that emscripten_audio_context_sample_rate() works.
   @requires_sound_hardware
diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index f6cb57c92bb93..30dfe629f94bc 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -3,8 +3,6 @@
 #include <emscripten/webaudio.h>
 #include <assert.h>
 
-#define QUIET_AUDIO_WORKLET
-
 // Tests that these audio worklet compatible functions work, details in comments below:
 //
 // - _emscripten_thread_supports_atomics_wait()
@@ -16,6 +14,7 @@
 // - emscripten_get_now()
 //
 // Define TEST_ON_WORKER to run on a worker, otherwise it runs on the main thread
+// Define QUIET_AUDIO_WORKLET to remove emscripten_out() calls in the audio worker
 
 // Global audio context
 EMSCRIPTEN_WEBAUDIO_T context;

From 70c1930911e2d823b264ebe3090900d4b610c93d Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 18:34:42 +0100
Subject: [PATCH 16/22] Minor renaming

---
 test/webaudio/audioworklet_emscripten_locks.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 30dfe629f94bc..78dbf355c874b 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -13,8 +13,8 @@
 // - emscripten_lock_release()
 // - emscripten_get_now()
 //
-// Define TEST_ON_WORKER to run on a worker, otherwise it runs on the main thread
-// Define QUIET_AUDIO_WORKLET to remove emscripten_out() calls in the audio worker
+// Define RUN_ON_WORKER to run on a worker, otherwise it runs on the main thread
+// Define QUIET_AUDIO_WORKLET to remove emscripten_out() calls in the audio worklet
 
 // Global audio context
 EMSCRIPTEN_WEBAUDIO_T context;
@@ -55,7 +55,7 @@ double startTime = 0;
 void do_exit() {
   emscripten_out("Test success");
   emscripten_destroy_audio_context(context);
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
   emscripten_terminate_all_wasm_workers();
 #endif
   emscripten_force_exit(0);
@@ -148,14 +148,14 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   };
 });
 
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
 void WorkerLoop() {
 #else
 bool MainLoop(double time, void* data) {
 #endif
   assert(!emscripten_current_thread_is_audio_worklet());
   int didUnlock = false;
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
   while (true) {
 #endif
 	  switch (whichTest) {
@@ -179,7 +179,7 @@ bool MainLoop(double time, void* data) {
 		break;
 	  case TEST_DONE:
 		// Finished, exit from the main thread (and return out of this loop)
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
 		emscripten_wasm_worker_post_function_v(EMSCRIPTEN_WASM_WORKER_ID_PARENT, &do_exit);
         // WorkerLoop contract (end the worker)
 		return;
@@ -191,7 +191,7 @@ bool MainLoop(double time, void* data) {
 	  default:
 		break;
 	  }
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
     // Repeat every 10ms (except when TEST_DONE)
     emscripten_wasm_worker_sleep(10 * 1000000ULL);
   }
@@ -230,7 +230,7 @@ int main() {
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
 
   // Either call every 10ms or create a worker that sleeps every 10ms
-#ifdef TEST_ON_WORKER
+#ifdef RUN_ON_WORKER
   emscripten_wasm_worker_t worker = emscripten_malloc_wasm_worker(1024);
   emscripten_wasm_worker_post_function_v(worker, WorkerLoop);
 #else

From 4cb45b066529f8f528100e4992b2fae80137ed39 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 18:37:21 +0100
Subject: [PATCH 17/22] Minor: moved out until after release

---
 test/webaudio/audioworklet_emscripten_locks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 78dbf355c874b..d7ad522f4ec85 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -165,9 +165,9 @@ bool MainLoop(double time, void* data) {
 		break;
 	  case TEST_WAIT_ACQUIRE:
 		if (!didUnlock) {
-		  emscripten_out("Worker/main releasing lock");
 		  // Release here to acquire in process
 		  emscripten_lock_release(&testLock);
+		  emscripten_out("TEST_WAIT_ACQUIRE: worker/main released lock");
 		  didUnlock = true;
 		}
 		break;

From 65231aba3f5093f4f9118e3aabd84641d4622a62 Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 18:39:55 +0100
Subject: [PATCH 18/22] Quiet printing throughout

---
 test/webaudio/audioworklet_emscripten_locks.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index d7ad522f4ec85..73bd12c853f9f 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -14,7 +14,7 @@
 // - emscripten_get_now()
 //
 // Define RUN_ON_WORKER to run on a worker, otherwise it runs on the main thread
-// Define QUIET_AUDIO_WORKLET to remove emscripten_out() calls in the audio worklet
+// Define QUIETEN_PRINTING to remove most of the emscripten_out() calls
 
 // Global audio context
 EMSCRIPTEN_WEBAUDIO_T context;
@@ -71,7 +71,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
   case TEST_HAS_WAIT:
     // Should not have wait support here
     result = _emscripten_thread_supports_atomics_wait();
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_HAS_WAIT: %d (expect: 0)", result);
 #endif
     assert(!result);
@@ -80,7 +80,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
   case TEST_TRY_ACQUIRE:
     // Was locked after init, should fail to acquire
     result = emscripten_lock_try_acquire(&testLock);
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_TRY_ACQUIRE: %d (expect: 0)", result);
 #endif
     assert(!result);
@@ -89,7 +89,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
   case TEST_WAIT_ACQUIRE_FAIL:
     // Still locked so we fail to acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 100);
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_WAIT_ACQUIRE_FAIL: %d (expect: 0)", result);
 #endif
     assert(!result);
@@ -98,7 +98,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
   case TEST_WAIT_ACQUIRE:
     // Will get unlocked in worker/main, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 1000);
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_WAIT_ACQUIRE: %d  (expect: 1)", result);
 #endif
     assert(result);
@@ -108,7 +108,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     // Unlock, check the result
     emscripten_lock_release(&testLock);
     result = emscripten_lock_try_acquire(&testLock);
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_RELEASE: %d (expect: 1)", result);
 #endif
     assert(result);
@@ -123,7 +123,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     break;
   case TEST_GET_NOW:
     result = (int) (emscripten_get_now() - startTime);
-#ifndef QUIET_AUDIO_WORKLET
+#ifndef QUIETEN_PRINTING
     emscripten_outf("TEST_GET_NOW: %d  (expect: > 0)", result);
 #endif
     assert(result > 0);
@@ -167,7 +167,9 @@ bool MainLoop(double time, void* data) {
 		if (!didUnlock) {
 		  // Release here to acquire in process
 		  emscripten_lock_release(&testLock);
+#ifndef QUIETEN_PRINTING
 		  emscripten_out("TEST_WAIT_ACQUIRE: worker/main released lock");
+#endif
 		  didUnlock = true;
 		}
 		break;
@@ -175,7 +177,9 @@ bool MainLoop(double time, void* data) {
 		// Spin here until released in process (but don't change test until we know this case ran)
 		whichTest = TEST_WAIT_INFINTE_2;
 		emscripten_lock_busyspin_waitinf_acquire(&testLock);
+#ifndef QUIETEN_PRINTING
 		emscripten_out("TEST_WAIT_INFINTE (from worker/main)");
+#endif
 		break;
 	  case TEST_DONE:
 		// Finished, exit from the main thread (and return out of this loop)

From 55c6569b8043b11f1c262182c245577be137277b Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Wed, 12 Nov 2025 18:59:15 +0100
Subject: [PATCH 19/22] Missed rename

---
 test/test_browser.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/test_browser.py b/test/test_browser.py
index f563bebea4c4a..aa4bdcee7b672 100644
--- a/test/test_browser.py
+++ b/test/test_browser.py
@@ -5619,7 +5619,7 @@ def test_audio_worklet_params_mixing(self, args):
   @also_with_minimal_runtime
   @flaky('https://github.com/emscripten-core/emscripten/issues/25245')
   def test_audio_worklet_emscripten_locks(self):
-    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread', '-DTEST_ON_WORKER'])
+    self.btest_exit('webaudio/audioworklet_emscripten_locks.c', cflags=['-sAUDIO_WORKLET', '-sWASM_WORKERS', '-pthread', '-DRUN_ON_WORKER'])
 
   # Verifies setting audio context sample rate, and that emscripten_audio_context_sample_rate() works.
   @requires_sound_hardware

From 055df5f26429b6659fc8ea175321d60a924841ca Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Fri, 14 Nov 2025 11:42:12 +0100
Subject: [PATCH 20/22] Minor tidy

---
 test/webaudio/audioworklet_emscripten_locks.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 73bd12c853f9f..5318d75fb89c1 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -95,6 +95,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
     assert(!result);
     whichTest = TEST_WAIT_ACQUIRE;
     // Fall through here so the worker/main has a chance to unlock whilst spinning
+    // (otherwise the lock has a chance to be released before spinning).
   case TEST_WAIT_ACQUIRE:
     // Will get unlocked in worker/main, so should quickly acquire
     result = emscripten_lock_busyspin_wait_acquire(&testLock, 1000);
@@ -145,16 +146,19 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   audioContext = emscriptenGetAudioObject(audioContext);
   startButton.onclick = () => {
     audioContext.resume();
+    document.removeChild(startButton);
   };
 });
 
+// Has TEST_WAIT_ACQUIRE unlocked testLock?
+int waitAcquireUnlocked = false;
+
 #ifdef RUN_ON_WORKER
 void WorkerLoop() {
 #else
 bool MainLoop(double time, void* data) {
 #endif
   assert(!emscripten_current_thread_is_audio_worklet());
-  int didUnlock = false;
 #ifdef RUN_ON_WORKER
   while (true) {
 #endif
@@ -164,13 +168,13 @@ bool MainLoop(double time, void* data) {
 		whichTest = TEST_HAS_WAIT;
 		break;
 	  case TEST_WAIT_ACQUIRE:
-		if (!didUnlock) {
+		if (!waitAcquireUnlocked) {
 		  // Release here to acquire in process
 		  emscripten_lock_release(&testLock);
 #ifndef QUIETEN_PRINTING
 		  emscripten_out("TEST_WAIT_ACQUIRE: worker/main released lock");
 #endif
-		  didUnlock = true;
+		  waitAcquireUnlocked = true;
 		}
 		break;
 	  case TEST_WAIT_INFINTE_1:
@@ -210,7 +214,6 @@ void AudioWorkletProcessorCreated(EMSCRIPTEN_WEBAUDIO_T audioContext, bool succe
   EmscriptenAudioWorkletNodeCreateOptions options = { .numberOfInputs = 0, .numberOfOutputs = 1, .outputChannelCounts = outputChannelCounts };
   EMSCRIPTEN_AUDIO_WORKLET_NODE_T wasmAudioWorklet = emscripten_create_wasm_audio_worklet_node(audioContext, "locks-test", &options, &ProcessAudio, NULL);
   emscripten_audio_node_connect(wasmAudioWorklet, audioContext, 0, 0);
-  InitHtmlUi(audioContext);
 }
 
 void WebAudioWorkletThreadInitialized(EMSCRIPTEN_WEBAUDIO_T audioContext, bool success, void *userData) {
@@ -231,6 +234,7 @@ int main() {
   // Audio processor callback setup
   context = emscripten_create_audio_context(NULL);
   assert(context);
+  InitHtmlUi(context);
   emscripten_start_wasm_audio_worklet_thread_async(context, wasmAudioWorkletStack, sizeof(wasmAudioWorkletStack), WebAudioWorkletThreadInitialized, NULL);
 
   // Either call every 10ms or create a worker that sleeps every 10ms

From 409a7d85b68c3cb5b8abb60342f58b8757d58adc Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Fri, 14 Nov 2025 11:49:36 +0100
Subject: [PATCH 21/22] Fix button removal

---
 test/webaudio/audioworklet_emscripten_locks.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 5318d75fb89c1..0b846628a7754 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -146,7 +146,7 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   audioContext = emscriptenGetAudioObject(audioContext);
   startButton.onclick = () => {
     audioContext.resume();
-    document.removeChild(startButton);
+    document.body.removeChild(startButton);
   };
 });
 

From e12e8a3a179493eec27c0bc299577dd12da6cf0c Mon Sep 17 00:00:00 2001
From: Carl Woffenden <cwoffenden@gmail.com>
Date: Fri, 14 Nov 2025 14:03:54 +0100
Subject: [PATCH 22/22] Minor tidy (and another run)

---
 test/webaudio/audioworklet_emscripten_locks.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/test/webaudio/audioworklet_emscripten_locks.c b/test/webaudio/audioworklet_emscripten_locks.c
index 0b846628a7754..517e79ae31a27 100644
--- a/test/webaudio/audioworklet_emscripten_locks.c
+++ b/test/webaudio/audioworklet_emscripten_locks.c
@@ -51,6 +51,8 @@ emscripten_lock_t testLock = EMSCRIPTEN_LOCK_T_STATIC_INITIALIZER;
 _Atomic Test whichTest = TEST_NOT_STARTED;
 // Time at which the test starts taken in main()
 double startTime = 0;
+// Has TEST_WAIT_ACQUIRE unlocked testLock?
+int waitAcquireUnlocked = false;
 
 void do_exit() {
   emscripten_out("Test success");
@@ -140,7 +142,7 @@ bool ProcessAudio(int numInputs, const AudioSampleFrame *inputs, int numOutputs,
 
 EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   let startButton = document.createElement('button');
-  startButton.innerHTML = 'Start playback';
+  startButton.innerHTML = 'Start Test';
   document.body.appendChild(startButton);
 
   audioContext = emscriptenGetAudioObject(audioContext);
@@ -150,9 +152,6 @@ EM_JS(void, InitHtmlUi, (EMSCRIPTEN_WEBAUDIO_T audioContext), {
   };
 });
 
-// Has TEST_WAIT_ACQUIRE unlocked testLock?
-int waitAcquireUnlocked = false;
-
 #ifdef RUN_ON_WORKER
 void WorkerLoop() {
 #else