Backport fix for screen not refreshing properly

Resolves: RHEL-89352

0001-compositor-x11-sync-again-at-the-end-of-before_paint.patch

@@ -0,0 +1,85 @@
+From f606a4424a5afc71672566b15f56971bfb7fa4db Mon Sep 17 00:00:00 2001
+From: Daniel van Vugt <daniel.van.vugt@canonical.com>
+Date: Fri, 16 Feb 2024 16:57:55 +0800
+Subject: [PATCH] compositor/x11: Sync again at the end of before_paint
+
+The existing comment tells us this is necessary:
+
+> there may be drawing between the last damage event and the
+> XDamageSubtract() that needs to be flushed as well.
+
+But the commit message for 551101c65cda also tells us that
+synchronization is necessary before-update. Assuming both are correct
+then it needs to be done in both places.
+
+I did try optimizing out the second sync to only do it if damage
+arrived during the update, but that doesn't seem to be the issue.
+The damage event is arriving before the update starts and it's some
+secondary changes within the damage region running late that need
+flushing. So this means the client is reporting damage more frequently
+than the frame rate and we're ignoring the secondary damage reports
+for efficiency (XDamageReportBoundingBox), which is still a good thing.
+
+Fixes: 551101c65cda ("compositor-x11: Move synchronization to before-update")
+Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/2880
+Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3590>
+---
+ src/compositor/meta-compositor-x11.c | 30 ++++++++++++++++++++++++----
+ 1 file changed, 26 insertions(+), 4 deletions(-)
+
+diff --git a/src/compositor/meta-compositor-x11.c b/src/compositor/meta-compositor-x11.c
+index 1d0ba4c..8bfd4c1 100644
+--- a/src/compositor/meta-compositor-x11.c
++++ b/src/compositor/meta-compositor-x11.c
+@@ -326,9 +326,7 @@ out:
+ }
+ 
+ static void
+-on_before_update (ClutterStage     *stage,
+-                  ClutterStageView *stage_view,
+-                  MetaCompositor   *compositor)
++maybe_do_sync (MetaCompositor *compositor)
+ {
+   MetaCompositorX11 *compositor_x11 = META_COMPOSITOR_X11 (compositor);
+ 
+@@ -363,6 +361,14 @@ on_before_update (ClutterStage     *stage,
+     }
+ }
+ 
++static void
++on_before_update (ClutterStage     *stage,
++                  ClutterStageView *stage_view,
++                  MetaCompositor   *compositor)
++{
++  maybe_do_sync (compositor);
++}
++
+ static void
+ on_after_update (ClutterStage     *stage,
+                  ClutterStageView *stage_view,
+@@ -390,6 +396,22 @@ meta_compositor_x11_before_paint (MetaCompositor   *compositor,
+ 
+   parent_class = META_COMPOSITOR_CLASS (meta_compositor_x11_parent_class);
+   parent_class->before_paint (compositor, stage_view);
++
++  /* We must sync after MetaCompositor's before_paint because that's the final
++   * time XDamageSubtract may happen before painting (when it calls
++   * meta_window_actor_x11_before_paint -> handle_updates ->
++   * meta_surface_actor_x11_handle_updates). If a client was to redraw between
++   * the last damage event and XDamageSubtract, and the bounding box of the
++   * region didn't grow, then we will not receive a new damage report for it
++   * (because XDamageReportBoundingBox). Then if we haven't synchronized again
++   * and the same region doesn't change on subsequent frames, we have lost some
++   * part of the update from the client. So to ensure the correct pixels get
++   * composited we must sync at least once between XDamageSubtract and
++   * compositing, which is here. More related documentation can be found in
++   * maybe_do_sync.
++   */
++
++  maybe_do_sync (compositor);
+ }
+ 
+ static void
+-- 
+GitLab
+

mutter.spec

@@ -10,7 +10,7 @@
 
 Name:          mutter
 Version:       40.9
-Release:       27%{?dist}
+Release:       28%{?dist}
 Summary:       Window and compositing manager based on Clutter
 
 License:       GPLv2+
@@ -165,6 +165,9 @@ Patch71: 0003-Use-access-instead-of-checking-permission-modes-for-.patch
 # RHEL-4521
 Patch72: fix-cogl-framebuffer-get-bits-test.patch
 
+# RHEL-89352
+Patch73: 0001-compositor-x11-sync-again-at-the-end-of-before_paint.patch
+
 BuildRequires: chrpath
 BuildRequires: pango-devel
 BuildRequires: startup-notification-devel
@@ -312,6 +315,10 @@ desktop-file-validate %{buildroot}/%{_datadir}/applications/%{name}.desktop
 %{_datadir}/mutter-%{mutter_api_version}/tests
 
 %changelog
+* Tue Jul 01 2025 Jan Grulich <jgrulich@redhat.com> - 40.9-28
+- Backport fix for screen not refreshing properly
+  Resolves: RHEL-89352
+
 * Fri Jun 27 2025 Jonas Ådahl <jadahl@redhat.com> - 40.9-27
 - Backport fixes for cogl OpenGL conformance
   Resolves: RHEL-4521