[Bf-blender-cvs] [8d25aeb6a63] cycles-x: Fix T91489: Cycles X crash when running with MESA_NO_ERROR

[Brecht Van Lommel]

Commit: 8d25aeb6a631fc941be72827134dec5b589e9ed4
Author: Brecht Van Lommel
Date:   Fri Sep 17 19:22:46 2021 +0200
Branches: cycles-x
https://developer.blender.org/rB8d25aeb6a631fc941be72827134dec5b589e9ed4

Fix T91489: Cycles X crash when running with MESA_NO_ERROR

===================================================================

M	intern/cycles/blender/blender_gpu_display.cpp

===================================================================

diff --git a/intern/cycles/blender/blender_gpu_display.cpp b/intern/cycles/blender/blender_gpu_display.cpp
index 5d3ae9ea4bc..a79232af71f 100644
--- a/intern/cycles/blender/blender_gpu_display.cpp
+++ b/intern/cycles/blender/blender_gpu_display.cpp
@@ -309,7 +309,9 @@ bool BlenderGPUDisplay::do_update_begin(const GPUDisplayParams &params,
     return false;
   }
 
-  glWaitSync((GLsync)gl_render_sync_, 0, GL_TIMEOUT_IGNORED);
+  if (gl_render_sync_) {
+    glWaitSync((GLsync)gl_render_sync_, 0, GL_TIMEOUT_IGNORED);
+  }
 
   if (!gl_texture_resources_ensure()) {
     gl_context_disable();
@@ -492,7 +494,9 @@ void BlenderGPUDisplay::do_draw(const GPUDisplayParams &params)
     gl_context_mutex_.lock();
   }
 
-  glWaitSync((GLsync)gl_upload_sync_, 0, GL_TIMEOUT_IGNORED);
+  if (gl_upload_sync_) {
+    glWaitSync((GLsync)gl_upload_sync_, 0, GL_TIMEOUT_IGNORED);
+  }
 
   if (transparent) {
     glEnable(GL_BLEND);