ui/gtk-egl: Check EGLSurface before doing scanout

The first time gd_egl_scanout_texture() is called, there's a possibility
that the GTK drawing area might not be realized yet, in which case its
associated GdkWindow is NULL. This means gd_egl_init() was also skipped
and the EGLContext and EGLSurface stored in the VirtualGfxConsole are
not valid yet.

Continuing with the scanout in this conditions would result in hitting
an assert in libepoxy: "Couldn't find current GLX or EGL context".

A possible workaround is to just ignore the scanout request, giving the
the GTK drawing area some time to finish its realization. At that point,
the gd_egl_init() will succeed and the EGLContext and EGLSurface stored
in the VirtualGfxConsole will be valid.

Signed-off-by: Antonio Caggiano <quic_acaggian@quicinc.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20231016123215.2699269-1-quic_acaggian@quicinc.com>
(cherry picked from commit 6f189a08c1b0085808af1bfbf4567f0da193ecc1)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index 52c6246a3353000b5a83af664e608e9e027fd809..17755b1185dd3dba0ea056f0a3ef7ced9353f1c0 100644 (file)
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -234,12 +234,19 @@ void gd_egl_scanout_texture(DisplayChangeListener *dcl,
     vc->gfx.h = h;
     vc->gfx.y0_top = backing_y_0_top;
 
-    eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
-                   vc->gfx.esurface, vc->gfx.ectx);
+    if (!vc->gfx.esurface) {
+        gd_egl_init(vc);
+        if (!vc->gfx.esurface) {
+            return;
+        }
 
-    gtk_egl_set_scanout_mode(vc, true);
-    egl_fb_setup_for_tex(&vc->gfx.guest_fb, backing_width, backing_height,
-                         backing_id, false);
+        eglMakeCurrent(qemu_egl_display, vc->gfx.esurface,
+                       vc->gfx.esurface, vc->gfx.ectx);
+
+        gtk_egl_set_scanout_mode(vc, true);
+        egl_fb_setup_for_tex(&vc->gfx.guest_fb, backing_width, backing_height,
+                             backing_id, false);
+    }
 }
 
 void gd_egl_scanout_dmabuf(DisplayChangeListener *dcl,