drmdev: call release callback before scanout callback

Call the release callback for the commit that is no longer visible on screen before calling the scanout callback.

The scanout callback might already start a new frame, and the release callback releases some resources that could be useful for building the new frame, so this helps avoid resource exhaustion.

Author: ardera

src/kms/drmdev.c

@@ -306,13 +306,13 @@ static void drmdev_on_page_flip(
         ASSERT_ZERO(ok);
     }
 
-    if (cbs_copy.callbacks[cbs_copy.index].scanout_callback != NULL) {
-        cbs_copy.callbacks[cbs_copy.index].scanout_callback(vblank_ns, cbs_copy.callbacks[cbs_copy.index].scanout_callback_userdata);
-    }
-
     if (cbs_copy.callbacks[cbs_copy.index].void_callback != NULL) {
         cbs_copy.callbacks[cbs_copy.index].void_callback(cbs_copy.callbacks[cbs_copy.index].void_callback_userdata);
     }
+
+    if (cbs_copy.callbacks[cbs_copy.index].scanout_callback != NULL) {
+        cbs_copy.callbacks[cbs_copy.index].scanout_callback(vblank_ns, cbs_copy.callbacks[cbs_copy.index].scanout_callback_userdata);
+    }
 }
 
 static void on_page_flip(