[mutter] onscreen/native: Don't try rendering on a secondary GPU without EGL

[Marge Bot <marge-bot src gnome org>]

commit 41bfabad96ee7c829ed17b585a752f3e676f6ab4
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Fri Mar 18 18:23:29 2022 +0800

    onscreen/native: Don't try rendering on a secondary GPU without EGL
    
    We rather confusingly still call a secondary display card that is
    GPU-less (DisplayLink or other basic KMS device) a "secondary GPU",
    so just because secondary_gpu_state is non-NULL doesn't mean we
    can use it for rendering. The clearest indication of this is when
    there is no EGL surface.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2341>

 src/backends/native/meta-onscreen-native.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/src/backends/native/meta-onscreen-native.c b/src/backends/native/meta-onscreen-native.c
index 3eb5503193..f2c2090dd1 100644
--- a/src/backends/native/meta-onscreen-native.c
+++ b/src/backends/native/meta-onscreen-native.c
@@ -757,6 +757,10 @@ copy_shared_framebuffer_primary_gpu (CoglOnscreen                        *onscre
   COGL_TRACE_BEGIN_SCOPED (CopySharedFramebufferPrimaryGpu,
                            "FB Copy (primary GPU)");
 
+  if (!secondary_gpu_state ||
+      secondary_gpu_state->egl_surface == EGL_NO_SURFACE)
+    return FALSE;
+
   primary_gpu = meta_renderer_native_get_primary_gpu (renderer_native);
   primary_gpu_data =
     meta_renderer_native_get_gpu_data (renderer_native, primary_gpu);