tor-browser

commit a17d30fdccc1e5f442b88787647947bcc42e97e8
parent c1fbf0df4af5e490088e9e7f95b5b974666aa047
Author: Brad Werth <werth@efn.org>
Date:   Tue, 16 Dec 2025 17:43:09 +0000

Bug 1985140 Part 3: Make OSXVsyncSource give up when display reconfiguration fails. r=mstange

This adds a method gfxPlatform::ResetHardwareVsyncSource to allow a
hardware vsync source to remove itself when needed. The OSXVsyncSource
now calls this method when display reconfiguration fails, and the
time-delayed retry *also* fails. This allows a software vsync method to
be used as a fallback, ensuring that some vsync source is active.

Differential Revision: https://phabricator.services.mozilla.com/D273131

Diffstat:
M
gfx/thebes/gfxPlatform.cpp
 | 
8
++++++++
M
gfx/thebes/gfxPlatform.h
 | 
6
++++++
M
gfx/thebes/gfxPlatformMac.cpp
 | 
23
+++++++++++++++++------

3 files changed, 31 insertions(+), 6 deletions(-)
diff --git a/gfx/thebes/gfxPlatform.cpp b/gfx/thebes/gfxPlatform.cpp
@@ -3553,6 +3553,14 @@ void gfxPlatform::ReInitFrameRate(const char* aPrefIgnored,
   gPlatform->mVsyncDispatcher->SetVsyncSource(vsyncSource);
 }
 
+/* static */
+void gfxPlatform::ResetHardwareVsyncSource() {
+  if (gPlatform->mGlobalHardwareVsyncSource) {
+    gPlatform->mGlobalHardwareVsyncSource->Shutdown();
+    gPlatform->mGlobalHardwareVsyncSource = nullptr;
+  }
+}
+
 const char* gfxPlatform::GetAzureCanvasBackend() const {
   BackendType backend{};
 
diff --git a/gfx/thebes/gfxPlatform.h b/gfx/thebes/gfxPlatform.h
@@ -689,6 +689,12 @@ class gfxPlatform : public mozilla::layers::MemoryPressureListener {
   static void ReInitFrameRate(const char* aPrefIgnored, void* aDataIgnored);
 
   /**
+   * Reset the global hardware vsync source. The next call to ReInitFrameRate
+   * will attempt to reestablish it, and fall back to software if needed.
+   */
+  static void ResetHardwareVsyncSource();
+
+  /**
    * Update force subpixel AA quality setting (called after pref
    * changes).
    */
diff --git a/gfx/thebes/gfxPlatformMac.cpp b/gfx/thebes/gfxPlatformMac.cpp
@@ -760,10 +760,7 @@ class OSXVsyncSource final : public VsyncSource {
 
   virtual ~OSXVsyncSource() {
     MOZ_ASSERT(NS_IsMainThread());
-    CGDisplayRemoveReconfigurationCallback(DisplayReconfigurationCallback,
-                                           this);
-    DisableVsync();
-    DestroyDisplayLink();
+    Shutdown();
   }
 
   static void RetryCreateDisplayLinkAndEnableVsync(nsITimer* aTimer,
@@ -772,8 +769,18 @@ class OSXVsyncSource final : public VsyncSource {
     OSXVsyncSource* osxVsyncSource =
         static_cast<OSXVsyncSource*>(aOsxVsyncSource);
     MOZ_ASSERT(osxVsyncSource);
+
+    osxVsyncSource->DisableVsync();
+    osxVsyncSource->DestroyDisplayLink();
     osxVsyncSource->CreateDisplayLink();
     osxVsyncSource->EnableVsync();
+
+    if (!osxVsyncSource->IsVsyncEnabled()) {
+      gfxWarning() << "Display reconfiguration vsync has failed; giving up.";
+      osxVsyncSource->Shutdown();
+      gfxPlatform::ResetHardwareVsyncSource();
+      gfxPlatform::ReInitFrameRate(nullptr, nullptr);
+    }
   }
 
   void CreateDisplayLink() {
@@ -891,8 +898,12 @@ class OSXVsyncSource final : public VsyncSource {
 
   void Shutdown() override {
     MOZ_ASSERT(NS_IsMainThread());
-    mTimer->Cancel();
-    mTimer = nullptr;
+    if (mTimer) {
+      mTimer->Cancel();
+      mTimer = nullptr;
+    }
+    CGDisplayRemoveReconfigurationCallback(DisplayReconfigurationCallback,
+                                           this);
     DisableVsync();
     DestroyDisplayLink();
   }