Display refreshment is invoked by a timer and it erroneously disables
the active scanout if it happens to be invoked after scanout has been
enabled. This offending scanout-disable race condition with a timer
can be easily hit when Qemu runs with a disabled vsync by using SDL or
GTK displays (with vblank_mode=0 for GTK). Refreshment of display's
content shouldn't disable the active display. Fix it by keeping the
scanout's state unchanged when display is redrawn.

Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
 ui/gtk-egl.c     | 1 -
 ui/gtk-gl-area.c | 1 -
 2 files changed, 2 deletions(-)

diff --git a/ui/gtk-egl.c b/ui/gtk-egl.c
index ae9239999cdb..0dbb429958e5 100644
--- a/ui/gtk-egl.c
+++ b/ui/gtk-egl.c
@@ -180,7 +180,6 @@ void gd_egl_refresh(DisplayChangeListener *dcl)
 
     if (vc->gfx.glupdates) {
         vc->gfx.glupdates = 0;
-        gtk_egl_set_scanout_mode(vc, false);
         gd_egl_draw(vc);
     }
 }
diff --git a/ui/gtk-gl-area.c b/ui/gtk-gl-area.c
index 05fc38096eca..88496c3dbfc6 100644
--- a/ui/gtk-gl-area.c
+++ b/ui/gtk-gl-area.c
@@ -184,7 +184,6 @@ void gd_gl_area_refresh(DisplayChangeListener *dcl)
 
     if (vc->gfx.glupdates) {
         vc->gfx.glupdates = 0;
-        gtk_gl_area_set_scanout_mode(vc, false);
         gtk_gl_area_queue_render(GTK_GL_AREA(vc->gfx.drawing_area));
     }
 }
-- 
2.51.0