From 8bea96d7018d02dff9462326ca9456f48e9fe9fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Thomas=20L=C3=BCbking?= <thomas.luebking@gmail.com>
Date: Fri, 9 Oct 2015 18:47:14 +0200
Subject: [PATCH] wait for GL after swapping

otherwise at least on the nvidia blob the swapping
doesn't block even for double buffering

REVIEW: 125659
BUG: 346275
CCBUG: 351700
FIXED-IN: 5.5
---
 glxbackend.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/glxbackend.cpp b/glxbackend.cpp
index 4c9e78c962..34408533e8 100644
--- a/glxbackend.cpp
+++ b/glxbackend.cpp
@@ -649,6 +649,10 @@ void GlxBackend::present()
                     }
                     setBlocksForRetrace(result == 'd');
                 }
+            } else if (blocksForRetrace()) {
+                // at least the nvidia blob manages to swap async, ie. return immediately on double
+                // buffering - what messes our timing calculation and leads to laggy behavior #346275
+                glXWaitGL();
             }
         } else {
             waitSync();