1 files changed, 113 insertions, 0 deletions
diff --git a/mozilla-1627469.patch b/mozilla-1627469.patch
new file mode 100644
index 0000000..3e53ec5
--- /dev/null
+++ b/mozilla-1627469.patch
@@ -0,0 +1,113 @@
+diff -up firefox-74.0.1/widget/gtk/WindowSurfaceWayland.cpp.mozilla-1627469 firefox-74.0.1/widget/gtk/WindowSurfaceWayland.cpp
+--- firefox-74.0.1/widget/gtk/WindowSurfaceWayland.cpp.mozilla-1627469	2020-04-06 15:07:16.772431937 +0200
++++ firefox-74.0.1/widget/gtk/WindowSurfaceWayland.cpp	2020-04-06 15:09:57.037320477 +0200
+@@ -647,13 +647,14 @@ WindowBackBuffer* WindowSurfaceWayland::
+   LOGWAYLAND(
+       ("WindowSurfaceWayland::NewWaylandBuffer [%p] Requested buffer [%d "
+        "x %d] DMABuf %d\n",
+-       (void*)this, mWidgetRect.width, mWidgetRect.height, aUseDMABufBackend));
++       (void*)this, mWLBufferRect.width, mWLBufferRect.height,
++       aUseDMABufBackend));
+ 
+   mWaylandBuffer = WaylandBufferFindAvailable(
+-      mWidgetRect.width, mWidgetRect.height, aUseDMABufBackend);
++      mWLBufferRect.width, mWLBufferRect.height, aUseDMABufBackend);
+   if (!mWaylandBuffer) {
+-    mWaylandBuffer = CreateWaylandBuffer(mWidgetRect.width, mWidgetRect.height,
+-                                         aUseDMABufBackend);
++    mWaylandBuffer = CreateWaylandBuffer(
++        mWLBufferRect.width, mWLBufferRect.height, aUseDMABufBackend);
+   }
+ 
+   return mWaylandBuffer;
+@@ -663,7 +664,7 @@ WindowBackBuffer* WindowSurfaceWayland::
+   LOGWAYLAND(
+       ("WindowSurfaceWayland::GetWaylandBufferRecent [%p] Requested buffer [%d "
+        "x %d]\n",
+-       (void*)this, mWidgetRect.width, mWidgetRect.height));
++       (void*)this, mWLBufferRect.width, mWLBufferRect.height));
+ 
+   // There's no buffer created yet, create a new one for partial screen updates.
+   if (!mWaylandBuffer) {
+@@ -675,9 +676,10 @@ WindowBackBuffer* WindowSurfaceWayland::
+     return nullptr;
+   }
+ 
+-  if (mWaylandBuffer->IsMatchingSize(mWidgetRect.width, mWidgetRect.height)) {
+-    LOGWAYLAND(("    Size is ok, use the buffer [%d x %d]\n", mWidgetRect.width,
+-                mWidgetRect.height));
++  if (mWaylandBuffer->IsMatchingSize(mWLBufferRect.width,
++                                     mWLBufferRect.height)) {
++    LOGWAYLAND(("    Size is ok, use the buffer [%d x %d]\n",
++                mWLBufferRect.width, mWLBufferRect.height));
+     return mWaylandBuffer;
+   }
+ 
+@@ -692,7 +694,7 @@ WindowBackBuffer* WindowSurfaceWayland::
+   LOGWAYLAND(
+       ("WindowSurfaceWayland::GetWaylandBufferWithSwitch [%p] Requested buffer "
+        "[%d x %d]\n",
+-       (void*)this, mWidgetRect.width, mWidgetRect.height));
++       (void*)this, mWLBufferRect.width, mWLBufferRect.height));
+ 
+   // There's no buffer created yet or actual buffer is attached, get a new one.
+   // Use DMABuf for fullscreen updates only.
+@@ -701,20 +703,21 @@ WindowBackBuffer* WindowSurfaceWayland::
+   }
+ 
+   // Reuse existing buffer
+-  LOGWAYLAND(("    Reuse buffer with resize [%d x %d]\n", mWidgetRect.width,
+-              mWidgetRect.height));
++  LOGWAYLAND(("    Reuse buffer with resize [%d x %d]\n", mWLBufferRect.width,
++              mWLBufferRect.height));
+ 
+   // OOM here, just return null to skip this frame.
+-  if (!mWaylandBuffer->Resize(mWidgetRect.width, mWidgetRect.height)) {
++  if (!mWaylandBuffer->Resize(mWLBufferRect.width, mWLBufferRect.height)) {
+     return nullptr;
+   }
+   return mWaylandBuffer;
+ }
+ 
+ already_AddRefed<gfx::DrawTarget> WindowSurfaceWayland::LockWaylandBuffer() {
+-  // Allocated wayland buffer must match widget size, otherwise wayland
+-  // compositor is confused and may produce various rendering artifacts.
+-  mWidgetRect = mWindow->GetMozContainerSize();
++  // Allocated wayland buffer can't be bigger than mozilla widget size.
++  LayoutDeviceIntRegion region;
++  region.And(mLockedScreenRect, mWindow->GetMozContainerSize());
++  mWLBufferRect = LayoutDeviceIntRect(region.GetBounds());
+ 
+   // mCanSwitchWaylandBuffer set means we're getting buffer for fullscreen
+   // update. We can use DMABuf and we can get a new buffer for drawing.
+@@ -882,8 +885,8 @@ already_AddRefed<gfx::DrawTarget> Window
+   LayoutDeviceIntRect size = mWindow->GetMozContainerSize();
+ 
+   // We can draw directly only when widget has the same size as wl_buffer
+-  mDrawToWaylandBufferDirectly = (size.width == mLockedScreenRect.width &&
+-                                  size.height == mLockedScreenRect.height);
++  mDrawToWaylandBufferDirectly = (size.width >= mLockedScreenRect.width &&
++                                  size.height >= mLockedScreenRect.height);
+ 
+   // We can draw directly only when we redraw significant part of the window
+   // to avoid flickering.
+diff -up firefox-74.0.1/widget/gtk/WindowSurfaceWayland.h.mozilla-1627469 firefox-74.0.1/widget/gtk/WindowSurfaceWayland.h
+--- firefox-74.0.1/widget/gtk/WindowSurfaceWayland.h.mozilla-1627469	2020-04-06 15:07:16.773431931 +0200
++++ firefox-74.0.1/widget/gtk/WindowSurfaceWayland.h	2020-04-06 15:07:16.775431919 +0200
+@@ -264,11 +264,11 @@ class WindowSurfaceWayland : public Wind
+   // mLockedScreenRect is window size when our wayland buffer was allocated.
+   LayoutDeviceIntRect mLockedScreenRect;
+ 
+-  // WidgetRect is an actual size of mozcontainer widget. It can be
+-  // different than mLockedScreenRect during resize when mBounds are updated
+-  // immediately but actual GtkWidget size is updated asynchronously
+-  // (see Bug 1489463).
+-  LayoutDeviceIntRect mWidgetRect;
++  // mWLBufferRect is an intersection of mozcontainer widgetsize and
++  // mLockedScreenRect size. It can be different than mLockedScreenRect
++  // during resize when mBounds are updated immediately but actual
++  // GtkWidget size is updated asynchronously (see Bug 1489463).
++  LayoutDeviceIntRect mWLBufferRect;
+   nsWaylandDisplay* mWaylandDisplay;
+ 
+   // Actual buffer (backed by wl_buffer) where all drawings go into.