[PATCH] ui/gtk: Wait until the current guest frame is rendered before switching to RUN_STATE_SAVE_VM

[dongwon . kim]

From: Dongwon <dongwon....@intel.com>

Make sure rendering of the current frame is finished before switching
the run state to RUN_STATE_SAVE_VM by waiting for egl-sync object to be
signaled.

Cc: Marc-André Lureau <marcandre.lur...@redhat.com>
Cc: Vivek Kasireddy <vivek.kasire...@intel.com>
Signed-off-by: Dongwon Kim <dongwon....@intel.com>
---
 ui/egl-helpers.c |  2 --
 ui/gtk.c         | 19 +++++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/ui/egl-helpers.c b/ui/egl-helpers.c
index 99b2ebbe23..dafeb36074 100644
--- a/ui/egl-helpers.c
+++ b/ui/egl-helpers.c
@@ -396,8 +396,6 @@ void egl_dmabuf_create_fence(QemuDmaBuf *dmabuf)
         fence_fd = eglDupNativeFenceFDANDROID(qemu_egl_display,
                                               sync);
         qemu_dmabuf_set_fence_fd(dmabuf, fence_fd);
-        eglDestroySyncKHR(qemu_egl_display, sync);
-        qemu_dmabuf_set_sync(dmabuf, NULL);
     }
 }
 
diff --git a/ui/gtk.c b/ui/gtk.c
index 93b13b7a30..cf0dd6abed 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -600,9 +600,12 @@ void gd_hw_gl_flushed(void *vcon)
 
     fence_fd = qemu_dmabuf_get_fence_fd(dmabuf);
     if (fence_fd >= 0) {
+        void *sync = qemu_dmabuf_get_sync(dmabuf);
         qemu_set_fd_handler(fence_fd, NULL, NULL, NULL);
         close(fence_fd);
         qemu_dmabuf_set_fence_fd(dmabuf, -1);
+        eglDestroySyncKHR(qemu_egl_display, sync);
+        qemu_dmabuf_set_sync(dmabuf, NULL);
         graphic_hw_gl_block(vc->gfx.dcl.con, false);
     }
 }
@@ -682,6 +685,22 @@ static const DisplayGLCtxOps egl_ctx_ops = {
 static void gd_change_runstate(void *opaque, bool running, RunState state)
 {
     GtkDisplayState *s = opaque;
+    QemuDmaBuf *dmabuf;
+    int i;
+
+    if (state == RUN_STATE_SAVE_VM) {
+        for (i = 0; i < s->nb_vcs; i++) {
+            VirtualConsole *vc = &s->vc[i];
+            dmabuf = vc->gfx.guest_fb.dmabuf;
+            if (dmabuf && qemu_dmabuf_get_fence_fd(dmabuf) >= 0) {
+                /* wait for the rendering to be completed */
+                eglClientWaitSync(qemu_egl_display,
+                                  qemu_dmabuf_get_sync(dmabuf),
+                                  EGL_SYNC_FLUSH_COMMANDS_BIT_KHR,
+                                  1000000000);
+            }
+        }
+    }
 
     gd_update_caption(s);
 }
-- 
2.34.1