From 6b4018014ca4dfe170d2ddab3873222acc3edcf0 Mon Sep 17 00:00:00 2001
From: David Redondo <kde@david-redondo.de>
Date: Thu, 8 Feb 2024 12:35:09 +0100
Subject: [PATCH] Guard against render time query failing

glGetQuery can fail (for example because of a context loss) in this
case the buffer stays unmodified. In this case this is zero resulting
in GLRenderTimeQuery::result() returning a negative value. Down the
line this leads to a negative duration in the RenderJournal and
RenderLoopPrivate::scheduleRepaint starting a timer with an amount
of milliseconds bigger than what an int can hold. This will not
actually start a timer but QTimer::isActive returns true resulting
in no futher repaints being scheduled.
BUG: 475605
FIXED-IN: 6.0
---
 src/opengl/glrendertimequery.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/opengl/glrendertimequery.cpp b/src/opengl/glrendertimequery.cpp
index 40dffc71bc..e299c358e1 100644
--- a/src/opengl/glrendertimequery.cpp
+++ b/src/opengl/glrendertimequery.cpp
@@ -56,6 +56,9 @@ std::chrono::nanoseconds GLRenderTimeQuery::result()
     if (m_query) {
         uint64_t nanos = 0;
         glGetQueryObjectui64v(m_query, GL_QUERY_RESULT, &nanos);
+        if (nanos == 0) {
+            return std::chrono::nanoseconds::zero();
+        }
         return std::chrono::nanoseconds(nanos) - m_cpuStart;
     } else {
         return m_cpuEnd - m_cpuStart;