From 967d9f32eaadb64961ec6638cc478ca3403b0329 Mon Sep 17 00:00:00 2001
From: Yuxuan Shui <yshuiv7@gmail.com>
Date: Sun, 9 Sep 2018 02:25:47 +0100
Subject: [PATCH] Workaround for what seems to be a race in Xserver

There seems to be a race between DamageAdd (what the client uses
to report damage to Xserver) and DamageSubtract (what compton uses
to clear the reported damage, so it can receive new ones). I am not
sure how to confirm this. But this (terrible) workaround seems to
solve this problem.
---
 src/compton.c | 8 ++------
 src/win.c     | 2 +-
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/compton.c b/src/compton.c
index d6e7cd1..61ff40b 100644
--- a/src/compton.c
+++ b/src/compton.c
@@ -2089,7 +2089,7 @@ paint_all(session_t *ps, XserverRegion region, XserverRegion region_real, win *t
 }
 
 static void
-repair_win(session_t *ps, win *w) {
+repair_win(session_t *ps, win *w, XDamageNotifyEvent *de) {
   if (IsViewable != w->a.map_state)
     return;
 
@@ -2097,12 +2097,8 @@ repair_win(session_t *ps, win *w) {
 
   if (!w->ever_damaged) {
     parts = win_extents(ps, w);
-    set_ignore_next(ps);
-    XDamageSubtract(ps->dpy, w->damage, None, None);
   } else {
-    parts = XFixesCreateRegion(ps->dpy, 0, 0);
-    set_ignore_next(ps);
-    XDamageSubtract(ps->dpy, w->damage, None, parts);
+    parts = XFixesCreateRegion(ps->dpy, (XRectangle[]){de->area}, 1);
     XFixesTranslateRegion(ps->dpy, parts,
       w->a.x + w->a.border_width,
       w->a.y + w->a.border_width);
diff --git a/src/win.c b/src/win.c
index 59ebee5..54871e4 100644
--- a/src/win.c
+++ b/src/win.c
@@ -878,7 +878,7 @@ bool add_win(session_t *ps, Window id, Window prev) {
 
     // Create Damage for window
     set_ignore_next(ps);
-    new->damage = XDamageCreate(ps->dpy, id, XDamageReportNonEmpty);
+    new->damage = XDamageCreate(ps->dpy, id, XDamageReportRawRectangles);
   }
 
   calc_win_size(ps, new);