Fix recorded render time when glXSwapBuffers() blocks

If glXSwapBuffers() blocks, the render loop will also record how long
kwin was blocked. Obviously, we don't want that.


(cherry picked from commit a78754b6)

composite.cpp

@@ -659,15 +659,10 @@ void Compositor::handleFrameRequested(RenderLoop *renderLoop)
         kwinApp()->platform()->createOpenGLSafePoint(Platform::OpenGLSafePoint::PreFrame);
     }
 
-    const std::chrono::milliseconds presentTime =
-            std::chrono::duration_cast<std::chrono::milliseconds>(renderLoop->nextPresentationTimestamp());
-
     const QRegion repaints = m_scene->repaints(screenId);
     m_scene->resetRepaints(screenId);
 
-    renderLoop->beginFrame();
-    m_scene->paint(screenId, repaints, windows, presentTime);
-    renderLoop->endFrame();
+    m_scene->paint(screenId, repaints, windows, renderLoop);
 
     if (m_framesToTestForSafety > 0) {
         if (m_scene->compositingType() & OpenGLCompositing) {

plugins/scenes/opengl/scene_opengl.cpp

@@ -33,6 +33,7 @@
 #include "lanczosfilter.h"
 #include "main.h"
 #include "overlaywindow.h"
+#include "renderloop.h"
 #include "screens.h"
 #include "cursor.h"
 #include "decorations/decoratedclient.h"
@@ -602,7 +603,7 @@ void SceneOpenGL::aboutToStartPainting(int screenId, const QRegion &damage)
 }
 
 void SceneOpenGL::paint(int screenId, const QRegion &damage, const QList<Toplevel *> &toplevels,
-                        std::chrono::milliseconds presentTime)
+                        RenderLoop *renderLoop)
 {
     if (m_resetOccurred) {
         return; // A graphics reset has occurred, do nothing.
@@ -639,9 +640,10 @@ void SceneOpenGL::paint(int screenId, const QRegion &damage, const QList<Topleve
     } else {
         int mask = 0;
         updateProjectionMatrix();
+        renderLoop->beginFrame();
 
         paintScreen(&mask, damage.intersected(geo), repaint, &update, &valid,
-                    presentTime, projectionMatrix(), geo, scaling);   // call generic implementation
+                    renderLoop, projectionMatrix(), geo, scaling);   // call generic implementation
         paintCursor(valid);
 
         if (!GLPlatform::instance()->isGLES() && screenId == -1) {
@@ -659,6 +661,8 @@ void SceneOpenGL::paint(int screenId, const QRegion &damage, const QList<Topleve
             }
         }
 
+        renderLoop->endFrame();
+
         GLVertexBuffer::streamingBuffer()->endOfFrame();
         m_backend->endFrame(screenId, valid, update);
         GLVertexBuffer::streamingBuffer()->framePosted();

plugins/scenes/opengl/scene_opengl.h

@@ -36,7 +36,7 @@ public:
     ~SceneOpenGL() override;
     bool initFailed() const override;
     void paint(int screenId, const QRegion &damage, const QList<Toplevel *> &windows,
-               std::chrono::milliseconds presentTime) override;
+               RenderLoop *renderLoop) override;
     Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
     Shadow *createShadow(Toplevel *toplevel) override;
     void screenGeometryChanged(const QSize &size) override;

plugins/scenes/qpainter/scene_qpainter.cpp

@@ -14,6 +14,7 @@
 #include "deleted.h"
 #include "effects.h"
 #include "main.h"
+#include "renderloop.h"
 #include "screens.h"
 #include "toplevel.h"
 #include "platform.h"
@@ -81,7 +82,7 @@ void SceneQPainter::paintGenericScreen(int mask, const ScreenPaintData &data)
 }
 
 void SceneQPainter::paint(int screenId, const QRegion &_damage, const QList<Toplevel *> &toplevels,
-                          std::chrono::milliseconds presentTime)
+                          RenderLoop *renderLoop)
 {
     Q_ASSERT(kwinApp()->platform()->isPerScreenRenderingEnabled());
     painted_screen = screenId;
@@ -100,15 +101,17 @@ void SceneQPainter::paint(int screenId, const QRegion &_damage, const QList<Topl
     const QRect geometry = screens()->geometry(screenId);
     QImage *buffer = m_backend->bufferForScreen(screenId);
     if (buffer && !buffer->isNull()) {
+        renderLoop->beginFrame();
         m_painter->begin(buffer);
         m_painter->setWindow(geometry);
 
         QRegion updateRegion, validRegion;
         paintScreen(&mask, damage.intersected(geometry), QRegion(), &updateRegion, &validRegion,
-                    presentTime);
+                    renderLoop);
         paintCursor(updateRegion);
 
         m_painter->end();
+        renderLoop->endFrame();
         m_backend->endFrame(screenId, mask, updateRegion);
     }
 

plugins/scenes/qpainter/scene_qpainter.h

@@ -27,7 +27,7 @@ public:
     bool usesOverlayWindow() const override;
     OverlayWindow* overlayWindow() const override;
     void paint(int screenId, const QRegion &damage, const QList<Toplevel *> &windows,
-               std::chrono::milliseconds presentTime) override;
+               RenderLoop *renderLoop) override;
     void paintGenericScreen(int mask, const ScreenPaintData &data) override;
     CompositingType compositingType() const override;
     bool initFailed() const override;

plugins/scenes/xrender/scene_xrender.cpp

@@ -23,6 +23,7 @@
 #include "main.h"
 #include "overlaywindow.h"
 #include "platform.h"
+#include "renderloop.h"
 #include "screens.h"
 #include "xcbutils.h"
 #include "decorations/decoratedclient.h"
@@ -76,7 +77,7 @@ bool SceneXrender::initFailed() const
 
 // the entry point for painting
 void SceneXrender::paint(int screenId, const QRegion &damage, const QList<Toplevel *> &toplevels,
-                         std::chrono::milliseconds presentTime)
+                         RenderLoop *renderLoop)
 {
     painted_screen = screenId;
 
@@ -84,7 +85,9 @@ void SceneXrender::paint(int screenId, const QRegion &damage, const QList<Toplev
 
     int mask = 0;
     QRegion updateRegion, validRegion;
-    paintScreen(&mask, damage, QRegion(), &updateRegion, &validRegion, presentTime);
+    renderLoop->beginFrame();
+    paintScreen(&mask, damage, QRegion(), &updateRegion, &validRegion, renderLoop);
+    renderLoop->endFrame();
 
     m_backend->showOverlay();
 

plugins/scenes/xrender/scene_xrender.h

@@ -33,7 +33,7 @@ public:
         return XRenderCompositing;
     }
     void paint(int screenId, const QRegion &damage, const QList<Toplevel *> &windows,
-               std::chrono::milliseconds presentTime) override;
+               RenderLoop *renderLoop) override;
     Scene::EffectFrame *createEffectFrame(EffectFrameImpl *frame) override;
     Shadow *createShadow(Toplevel *toplevel) override;
     void screenGeometryChanged(const QSize &size) override;

scene.cpp

@@ -146,8 +146,7 @@ void Scene::reallocRepaints()
 
 // returns mask and possibly modified region
 void Scene::paintScreen(int* mask, const QRegion &damage, const QRegion &repaint,
-                        QRegion *updateRegion, QRegion *validRegion,
-                        std::chrono::milliseconds presentTime,
+                        QRegion *updateRegion, QRegion *validRegion, RenderLoop *renderLoop,
                         const QMatrix4x4 &projection, const QRect &outputGeometry,
                         qreal screenScale)
 {
@@ -155,6 +154,9 @@ void Scene::paintScreen(int* mask, const QRegion &damage, const QRegion &repaint
     const QRegion displayRegion(0, 0, screenSize.width(), screenSize.height());
     *mask = (damage == displayRegion) ? 0 : PAINT_SCREEN_REGION;
 
+    const std::chrono::milliseconds presentTime =
+            std::chrono::duration_cast<std::chrono::milliseconds>(renderLoop->nextPresentationTimestamp());
+
     if (Q_UNLIKELY(presentTime < m_expectedPresentTimestamp)) {
         qCDebug(KWIN_CORE, "Provided presentation timestamp is invalid: %ld (current: %ld)",
                 presentTime.count(), m_expectedPresentTimestamp.count());

scene.h

@@ -39,6 +39,7 @@ class Deleted;
 class EffectFrameImpl;
 class EffectWindowImpl;
 class OverlayWindow;
+class RenderLoop;
 class Shadow;
 class WindowPixmap;
 class GLTexture;
@@ -75,7 +76,7 @@ public:
     // returns the time since the last vblank signal - if there's one
     // ie. "what of this frame is lost to painting"
     virtual void paint(int screenId, const QRegion &damage, const QList<Toplevel *> &windows,
-                       std::chrono::milliseconds presentTime) = 0;
+                       RenderLoop *renderLoop) = 0;
 
     /**
      * Adds the Toplevel to the Scene.
@@ -213,8 +214,7 @@ protected:
     void clearStackingOrder();
     // shared implementation, starts painting the screen
     void paintScreen(int *mask, const QRegion &damage, const QRegion &repaint,
-                     QRegion *updateRegion, QRegion *validRegion,
-                     std::chrono::milliseconds presentTime,
+                     QRegion *updateRegion, QRegion *validRegion, RenderLoop *renderLoop,
                      const QMatrix4x4 &projection = QMatrix4x4(),
                      const QRect &outputGeometry = QRect(), qreal screenScale = 1.0);
     // Render cursor texture in case hardware cursor is disabled/non-applicable