GLX: Always call XSync on creation/destruction of WindowSurfaces

src/libANGLE/renderer/gl/glx/DisplayGLX.cpp

@@ -334,7 +334,7 @@ egl::Error DisplayGLX::initialize(egl::Display *display)
         }
     }
 
-    syncXCommands();
+    syncXCommands(false);
 
     mRenderer.reset(new RendererGLX(std::move(functionsGL), eglAttributes, this));
     const gl::Version &maxVersion = mRenderer->getMaxSupportedESVersion();
@@ -825,9 +825,9 @@ gl::Version DisplayGLX::getMaxSupportedESVersion() const
     return mRenderer->getMaxSupportedESVersion();
 }
 
-void DisplayGLX::syncXCommands() const
+void DisplayGLX::syncXCommands(bool alwaysSync) const
 {
-    if (mUsesNewXDisplay)
+    if (mUsesNewXDisplay || alwaysSync)
     {
         XSync(mGLX.getDisplay(), False);
     }

src/libANGLE/renderer/gl/glx/DisplayGLX.h

@@ -75,11 +75,13 @@ class DisplayGLX : public DisplayGL
 
     gl::Version getMaxSupportedESVersion() const override;
 
-    // Synchronizes with the X server, if the display has been opened by ANGLE.
+    // Synchronizes with the X server.
     // Calling this is required at the end of every functions that does buffered
     // X calls (not for glX calls) otherwise there might be race conditions
     // between the application's display and ANGLE's one.
-    void syncXCommands() const;
+    // Calling this only syncs if ANGLE opened the display, or if alwaysSync
+    // is true.
+    void syncXCommands(bool alwaysSync) const;
 
     // Depending on the supported GLX extension, swap interval can be set
     // globally or per drawable. This function will make sure the drawable's

src/libANGLE/renderer/gl/glx/PixmapSurfaceGLX.cpp

@@ -132,7 +132,7 @@ egl::Error PixmapSurfaceGLX::initialize(const egl::Display *display)
     }
 
     XFlush(mDisplay);
-    displayGLX->syncXCommands();
+    displayGLX->syncXCommands(false);
 
     return egl::NoError();
 }

src/libANGLE/renderer/gl/glx/WindowSurfaceGLX.cpp

@@ -59,7 +59,7 @@ WindowSurfaceGLX::~WindowSurfaceGLX()
         XSetErrorHandler(oldErrorHandler);
     }
 
-    mGLXDisplay->syncXCommands();
+    mGLXDisplay->syncXCommands(true);
 }
 
 egl::Error WindowSurfaceGLX::initialize(const egl::Display *display)
@@ -141,7 +141,7 @@ egl::Error WindowSurfaceGLX::initialize(const egl::Display *display)
         XFreeColormap(mDisplay, colormap);
     }
 
-    mGLXDisplay->syncXCommands();
+    mGLXDisplay->syncXCommands(true);
 
     return egl::NoError();
 }