From d76e8131ac4c115b7a750c9f127f9fa920a9d094 Mon Sep 17 00:00:00 2001
From: =?utf8?q?Marek=20Ol=C5=A1=C3=A1k?= <marek.olsak@amd.com>
Date: Mon, 8 Jun 2020 08:46:10 -0400
Subject: [PATCH] glthread: sync in glFlush for multiple contexts

See the code comment.

Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5382>
---
 src/mapi/glapi/gen/gl_API.xml | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/mapi/glapi/gen/gl_API.xml b/src/mapi/glapi/gen/gl_API.xml
index b351166..0e164b4 100644
--- a/src/mapi/glapi/gen/gl_API.xml
+++ b/src/mapi/glapi/gen/gl_API.xml
@@ -2390,8 +2390,14 @@
         <glx sop="108" handcode="true"/>
     </function>
 
+    <!-- Shared contexts have to wait for glthread to finish execution after glFlush,
+         so that other contexts can see the effect of previous GL calls when glFlush returns.
+         This is harmless if the contexts run on different threads, because we only stall
+         1 thread that's asynchronous anyway. It's worse when the contexts run on the same
+         thread, but that's not a good use of multiple contexts.
+    -->
     <function name="Flush" es1="1.0" es2="2.0"
-              marshal_call_after="_mesa_glthread_flush_batch(ctx);">
+              marshal_call_after="_mesa_glthread_flush_batch(ctx); if (ctx->Shared->RefCount > 1) _mesa_glthread_finish(ctx);">
         <glx sop="142" handcode="true"/>
     </function>
 
-- 
2.7.4