diff --git a/gfx/gl/GLContextProviderGLX.cpp b/gfx/gl/GLContextProviderGLX.cpp
index 22ce61b7458..373c97ded24 100644
--- a/gfx/gl/GLContextProviderGLX.cpp
+++ b/gfx/gl/GLContextProviderGLX.cpp
@@ -169,12 +169,6 @@ GLXLibrary::EnsureInitialized()
         { nullptr, { nullptr } }
     };
 
-    GLLibraryLoader::SymLoadStruct symbols_videosync[] = {
-      { (PRFuncPtr*) &xGetVideoSyncInternal, { "glXGetVideoSyncSGI", nullptr } },
-      { (PRFuncPtr*) &xWaitVideoSyncInternal, { "glXWaitVideoSyncSGI", nullptr } },
-      { nullptr, { nullptr } }
-    };
-
     if (!GLLibraryLoader::LoadSymbols(mOGLLibrary, &symbols[0])) {
         NS_WARNING("Couldn't find required entry point in OpenGL shared library");
         return false;
@@ -252,13 +246,6 @@ GLXLibrary::EnsureInitialized()
         mHasRobustness = true;
     }
 
-    if (HasExtension(extensionsStr, "GLX_SGI_video_sync") &&
-        GLLibraryLoader::LoadSymbols(mOGLLibrary, symbols_videosync,
-                                     (GLLibraryLoader::PlatformLookupFunction)&xGetProcAddress))
-    {
-        mHasVideoSync = true;
-    }
-
     mIsATI = serverVendor && DoesStringMatch(serverVendor, "ATI");
     mIsNVIDIA = serverVendor && DoesStringMatch(serverVendor, "NVIDIA Corporation");
     mClientIsMesa = clientVendor && DoesStringMatch(clientVendor, "Mesa");
@@ -282,16 +269,6 @@ GLXLibrary::SupportsTextureFromPixmap(gfxASurface* aSurface)
     return true;
 }
 
-bool
-GLXLibrary::SupportsVideoSync()
-{
-    if (!EnsureInitialized()) {
-        return false;
-    }
-
-    return mHasVideoSync;
-}
-
 GLXPixmap
 GLXLibrary::CreatePixmap(gfxASurface* aSurface)
 {
@@ -760,24 +737,6 @@ GLXLibrary::xCreateContextAttribs(Display* display,
     return result;
 }
 
-int
-GLXLibrary::xGetVideoSync(unsigned int* count)
-{
-    BEFORE_GLX_CALL;
-    int result = xGetVideoSyncInternal(count);
-    AFTER_GLX_CALL;
-    return result;
-}
-
-int
-GLXLibrary::xWaitVideoSync(int divisor, int remainder, unsigned int* count)
-{
-    BEFORE_GLX_CALL;
-    int result = xWaitVideoSyncInternal(divisor, remainder, count);
-    AFTER_GLX_CALL;
-    return result;
-}
-
 already_AddRefed<GLContextGLX>
 GLContextGLX::CreateGLContext(
                   const SurfaceCaps& caps,
diff --git a/gfx/gl/GLXLibrary.h b/gfx/gl/GLXLibrary.h
index 687db73e8b8..7ce332fa7d7 100644
--- a/gfx/gl/GLXLibrary.h
+++ b/gfx/gl/GLXLibrary.h
@@ -54,12 +54,9 @@ public:
     , xWaitGLInternal(nullptr)
     , xWaitXInternal(nullptr)
     , xCreateContextAttribsInternal(nullptr)
-    , xGetVideoSyncInternal(nullptr)
-    , xWaitVideoSyncInternal(nullptr)
     , mInitialized(false), mTriedInitializing(false)
     , mUseTextureFromPixmap(false), mDebug(false)
     , mHasRobustness(false), mHasCreateContextAttribs(false)
-    , mHasVideoSync(false)
     , mIsATI(false), mIsNVIDIA(false)
     , mClientIsMesa(false), mGLXMajorVersion(0)
     , mGLXMinorVersion(0)
@@ -123,9 +120,6 @@ public:
                                      Bool direct,
                                      const int* attrib_list);
 
-    int xGetVideoSync(unsigned int* count);
-    int xWaitVideoSync(int divisor, int remainder, unsigned int* count);
-
     bool EnsureInitialized();
 
     GLXPixmap CreatePixmap(gfxASurface* aSurface);
@@ -138,7 +132,6 @@ public:
     bool HasRobustness() { return mHasRobustness; }
     bool HasCreateContextAttribs() { return mHasCreateContextAttribs; }
     bool SupportsTextureFromPixmap(gfxASurface* aSurface);
-    bool SupportsVideoSync();
     bool IsATI() { return mIsATI; }
     bool GLXVersionCheck(int aMajor, int aMinor);
 
@@ -232,12 +225,6 @@ private:
                                                                   const int *);
     PFNGLXCREATECONTEXTATTRIBS xCreateContextAttribsInternal;
 
-    typedef int (GLAPIENTRY *PFNGLXGETVIDEOSYNCSGI) (unsigned int *count);
-    PFNGLXGETVIDEOSYNCSGI xGetVideoSyncInternal;
-
-    typedef int (GLAPIENTRY *PFNGLXWAITVIDEOSYNCSGI) (int divisor, int remainder, unsigned int *count);
-    PFNGLXWAITVIDEOSYNCSGI xWaitVideoSyncInternal;
-
 #ifdef DEBUG
     void BeforeGLXCall();
     void AfterGLXCall();
@@ -249,7 +236,6 @@ private:
     bool mDebug;
     bool mHasRobustness;
     bool mHasCreateContextAttribs;
-    bool mHasVideoSync;
     bool mIsATI;
     bool mIsNVIDIA;
     bool mClientIsMesa;