Never use X11 EGL on Nvidia proprietary drivers

Fixes #1751

app/main.cpp

@@ -476,12 +476,18 @@ int main(int argc, char *argv[])
 #endif
     }
 
-    // Some ARM and RISC-V embedded devices don't have working GLX which can cause
-    // SDL to fail to find a working OpenGL implementation at all. Let's force EGL
-    // on all platforms for both SDL and Qt. This also avoids GLX-EGL interop issues
-    // when trying to use EGL on the main thread after Qt uses GLX.
-    SDL_SetHint(SDL_HINT_VIDEO_X11_FORCE_EGL, "1");
-    qputenv("QT_XCB_GL_INTEGRATION", "xcb_egl");
+    // Nvidia's proprietary driver has broken EGL support on X11, so don't use it.
+    // This will break the EGLRenderer, but that's fine on Nvidia because they
+    // support both VDPAU and Vulkan renderers instead.
+    // https://github.com/moonlight-stream/moonlight-qt/issues/1751
+    if (!WMUtils::isRunningX11NvidiaProprietaryDriver()) {
+        // Some ARM and RISC-V embedded devices don't have working GLX which can cause
+        // SDL to fail to find a working OpenGL implementation at all. Let's force EGL
+        // on all platforms for both SDL and Qt. This also avoids GLX-EGL interop issues
+        // when trying to use EGL on the main thread after Qt uses GLX.
+        SDL_SetHint(SDL_HINT_VIDEO_X11_FORCE_EGL, "1");
+        qputenv("QT_XCB_GL_INTEGRATION", "xcb_egl");
+    }
 
 #ifdef Q_OS_MACOS
     // This avoids using the default keychain for SSL, which may cause

app/streaming/video/ffmpeg-renderers/eglvid.cpp

@@ -434,6 +434,14 @@ bool EGLRenderer::initialize(PDECODER_PARAMETERS params)
         return false;
     }
 
+    // If we're using X11 GLX (both in SDL and Qt), don't use this renderer.
+    // Switching between EGL and GLX can cause interoperability issues.
+    if (strcmp(SDL_GetCurrentVideoDriver(), "x11") == 0 &&
+            !SDL_GetHintBoolean(SDL_HINT_VIDEO_X11_FORCE_EGL, SDL_FALSE)) {
+        EGL_LOG(Warn, "Disabled due to use of GLX");
+        return false;
+    }
+
     // This hint will ensure we use EGL to retrieve our GL context,
     // even on X11 where that is not the default. EGL is required
     // to avoid a crash in Mesa.
@@ -657,13 +665,6 @@ bool EGLRenderer::initialize(PDECODER_PARAMETERS params)
     // Detach the context from this thread, so the render thread can attach it
     SDL_GL_MakeCurrent(m_Window, nullptr);
 
-    if (err == GL_NO_ERROR) {
-        // If we got a working GL implementation via EGL, avoid using GLX from now on.
-        // GLX will cause problems if we later want to use EGL again on this window.
-        SDL_LogInfo(SDL_LOG_CATEGORY_APPLICATION, "EGL passed preflight checks. Using EGL for GL context creation.");
-        SDL_SetHint(SDL_HINT_VIDEO_X11_FORCE_EGL, "1");
-    }
-
     return err == GL_NO_ERROR;
 }
 

app/utils.h

@@ -7,6 +7,7 @@
 
 namespace WMUtils {
     bool isRunningX11();
+    bool isRunningX11NvidiaProprietaryDriver();
     bool isRunningWayland();
     bool isRunningWindowManager();
     bool isRunningDesktopEnvironment();

app/wm.cpp

@@ -47,6 +47,40 @@ bool WMUtils::isRunningX11()
     return false;
 }
 
+bool WMUtils::isRunningX11NvidiaProprietaryDriver()
+{
+#ifdef HAS_X11
+    static SDL_atomic_t isRunningOnX11NvidiaDriver;
+
+    // If the value is not set yet, populate it now.
+    int val = SDL_AtomicGet(&isRunningOnX11NvidiaDriver);
+    if (!(val & VALUE_SET)) {
+        Display* display = XOpenDisplay(nullptr);
+        bool nvidiaDriver = false;
+
+        if (display != nullptr) {
+            int opcode, event, error;
+
+            // We use the presence of the NV-CONTROL extension to indicate
+            // that the Nvidia proprietary driver is in use on native X11
+            nvidiaDriver = XQueryExtension(display, "NV-CONTROL", &opcode, &event, &error);
+
+            XCloseDisplay(display);
+        }
+
+        // Populate the value to return and have for next time.
+        // This can race with another thread populating the same data,
+        // but that's no big deal.
+        val = VALUE_SET | (nvidiaDriver ? VALUE_TRUE : 0);
+        SDL_AtomicSet(&isRunningOnX11NvidiaDriver, val);
+    }
+
+    return !!(val & VALUE_TRUE);
+#endif
+
+    return false;
+}
+
 bool WMUtils::isRunningWayland()
 {
 #ifdef HAS_WAYLAND