--- a/widget/src/xpwidgets/nsBaseWidget.cpp
+++ b/widget/src/xpwidgets/nsBaseWidget.cpp
@@ -788,16 +788,34 @@ nsBaseWidget::GetShouldAccelerate()
   PRBool forceAcceleration = PR_FALSE;
 #if defined(XP_WIN) || defined(ANDROID) || (MOZ_PLATFORM_MAEMO > 5)
   PRBool accelerateByDefault = PR_TRUE;
 #elif defined(XP_MACOSX)
 /* quickdraw plugins don't work with OpenGL so we need to avoid OpenGL when we want to support
  * them. e.g. 10.5 */
 # if defined(NP_NO_QUICKDRAW)
   PRBool accelerateByDefault = PR_TRUE;
+
+  // 10.6.2 and lower have a bug involving textures and pixel buffer objects
+  // that caused bug 629016, so we don't allow OpenGL-accelerated layers on
+  // those versions of the OS.
+  // This will still let full-screen video be accelerated on OpenGL, because
+  // that XUL widget opts in to acceleration, but that's probably OK.
+  SInt32 major, minor, bugfix;
+  OSErr err1 = ::Gestalt(gestaltSystemVersionMajor, &major);
+  OSErr err2 = ::Gestalt(gestaltSystemVersionMinor, &minor);
+  OSErr err3 = ::Gestalt(gestaltSystemVersionBugFix, &bugfix);
+  if (err1 == noErr && err2 == noErr && err3 == noErr) {
+    if (major == 10 && minor == 6) {
+      if (bugfix <= 2) {
+        accelerateByDefault = PR_FALSE;
+      }
+    }
+  }
+
 # else
   PRBool accelerateByDefault = PR_FALSE;
 # endif
 
 #else
   PRBool accelerateByDefault = PR_FALSE;
 #endif