These egl helpers would be used for creating and waiting on
a sync object.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 include/ui/console.h     |  2 ++
 include/ui/egl-helpers.h |  3 +++
 ui/egl-helpers.c         | 44 ++++++++++++++++++++++++++++++++++++++++
 ui/gtk.c                 | 15 ++++++++++++++
 4 files changed, 64 insertions(+)

diff --git a/include/ui/console.h b/include/ui/console.h
index c3dca61c31..a89f739f10 100644
--- a/include/ui/console.h
+++ b/include/ui/console.h
@@ -168,6 +168,8 @@ typedef struct QemuDmaBuf {
     uint64_t  modifier;
     uint32_t  texture;
     bool      y0_top;
+    void      *sync;
+    int       fence_fd;
 } QemuDmaBuf;
 
 typedef struct DisplayState DisplayState;
diff --git a/include/ui/egl-helpers.h b/include/ui/egl-helpers.h
index f1bf8f97fc..5a7575dc13 100644
--- a/include/ui/egl-helpers.h
+++ b/include/ui/egl-helpers.h
@@ -45,6 +45,9 @@ int egl_get_fd_for_texture(uint32_t tex_id, EGLint *stride, EGLint *fourcc,
 
 void egl_dmabuf_import_texture(QemuDmaBuf *dmabuf);
 void egl_dmabuf_release_texture(QemuDmaBuf *dmabuf);
+void egl_dmabuf_create_sync(QemuDmaBuf *dmabuf);
+void egl_dmabuf_create_fence(QemuDmaBuf *dmabuf);
+void egl_dmabuf_wait_sync(QemuDmaBuf *dmabuf);
 
 #endif
 
diff --git a/ui/egl-helpers.c b/ui/egl-helpers.c
index 6d0cb2b5cb..47220b66e0 100644
--- a/ui/egl-helpers.c
+++ b/ui/egl-helpers.c
@@ -76,6 +76,50 @@ void egl_fb_setup_for_tex(egl_fb *fb, int width, int height,
                               GL_TEXTURE_2D, fb->texture, 0);
 }
 
+void egl_dmabuf_create_sync(QemuDmaBuf *dmabuf)
+{
+    EGLSyncKHR sync;
+
+    if (epoxy_has_egl_extension(qemu_egl_display,
+                                "EGL_KHR_fence_sync") &&
+        epoxy_has_egl_extension(qemu_egl_display,
+                                "EGL_ANDROID_native_fence_sync")) {
+        sync = eglCreateSyncKHR(qemu_egl_display,
+				EGL_SYNC_NATIVE_FENCE_ANDROID, NULL);
+        if (sync != EGL_NO_SYNC_KHR) {
+            dmabuf->sync = sync;
+        }
+    }
+}
+
+void egl_dmabuf_create_fence(QemuDmaBuf *dmabuf)
+{
+    if (dmabuf->sync) {
+        dmabuf->fence_fd = eglDupNativeFenceFDANDROID(qemu_egl_display,
+                                                      dmabuf->sync);
+        eglDestroySyncKHR(qemu_egl_display, dmabuf->sync);
+        dmabuf->sync = NULL;
+    }
+}
+
+void egl_dmabuf_wait_sync(QemuDmaBuf *dmabuf)
+{
+    EGLSyncKHR sync;
+    EGLint attrib_list[] = {
+        EGL_SYNC_NATIVE_FENCE_FD_ANDROID, dmabuf->fence_fd,
+        EGL_NONE,
+    };
+
+    sync = eglCreateSyncKHR(qemu_egl_display,
+                            EGL_SYNC_NATIVE_FENCE_ANDROID, attrib_list);
+    if (sync != EGL_NO_SYNC_KHR) {
+        eglClientWaitSyncKHR(qemu_egl_display, sync,
+                             0, EGL_FOREVER_KHR);
+        eglDestroySyncKHR(qemu_egl_display, sync);
+        dmabuf->fence_fd = -1;
+    }
+}
+
 void egl_fb_setup_new_tex(egl_fb *fb, int width, int height)
 {
     GLuint texture;
diff --git a/ui/gtk.c b/ui/gtk.c
index 6132bab52f..cd884ca26c 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -583,6 +583,19 @@ static void gd_gl_release_dmabuf(DisplayChangeListener *dcl,
 #endif
 }
 
+static void gd_gl_wait_dmabuf(DisplayChangeListener *dcl,
+                              QemuDmaBuf *dmabuf)
+{
+#ifdef CONFIG_GBM
+    egl_dmabuf_create_fence(dmabuf);
+    if (dmabuf->fence_fd <= 0) {
+        return;
+    }
+
+    egl_dmabuf_wait_sync(dmabuf);
+#endif
+}
+
 /** DisplayState Callbacks (opengl version) **/
 
 static const DisplayChangeListenerOps dcl_gl_area_ops = {
@@ -602,6 +615,7 @@ static const DisplayChangeListenerOps dcl_gl_area_ops = {
     .dpy_gl_update           = gd_gl_area_scanout_flush,
     .dpy_gl_scanout_dmabuf   = gd_gl_area_scanout_dmabuf,
     .dpy_gl_release_dmabuf   = gd_gl_release_dmabuf,
+    .dpy_gl_wait_dmabuf      = gd_gl_wait_dmabuf,
     .dpy_has_dmabuf          = gd_has_dmabuf,
 };
 
@@ -626,6 +640,7 @@ static const DisplayChangeListenerOps dcl_egl_ops = {
     .dpy_gl_cursor_position  = gd_egl_cursor_position,
     .dpy_gl_update           = gd_egl_scanout_flush,
     .dpy_gl_release_dmabuf   = gd_gl_release_dmabuf,
+    .dpy_gl_wait_dmabuf      = gd_gl_wait_dmabuf,
     .dpy_has_dmabuf          = gd_has_dmabuf,
 };
 
-- 
2.30.2

  Hi,

> +        epoxy_has_egl_extension(qemu_egl_display,
> +                                "EGL_ANDROID_native_fence_sync")) {

What about non-android?  Is the name there just for historical reasons?
Or do we actually need something else for desktop systems?

> +void egl_dmabuf_wait_sync(QemuDmaBuf *dmabuf)

See other mail on blocking wait.  Otherwise looks sane.

> +static void gd_gl_wait_dmabuf(DisplayChangeListener *dcl,
> +                              QemuDmaBuf *dmabuf)

separate patch for the gtk bits please.

thanks,
  Gerd

Hi Gerd,
 
> > +        epoxy_has_egl_extension(qemu_egl_display,
> > +                                "EGL_ANDROID_native_fence_sync")) {
> 
> What about non-android?  Is the name there just for historical reasons?
> Or do we actually need something else for desktop systems?
[Kasireddy, Vivek] It is not specific to Android:
https://www.khronos.org/registry/EGL/extensions/ANDROID/EGL_ANDROID_native_fence_sync.txt

I have been using Linux (Fedora 33 for both Guest and Host) as my
test platform.

> 
> > +void egl_dmabuf_wait_sync(QemuDmaBuf *dmabuf)
> 
> See other mail on blocking wait.  Otherwise looks sane.
> 
> > +static void gd_gl_wait_dmabuf(DisplayChangeListener *dcl,
> > +                              QemuDmaBuf *dmabuf)
> 
> separate patch for the gtk bits please.
[Kasireddy, Vivek] Ok, will do.

Thanks,
Vivek

> 
> thanks,
>   Gerd