[plasma/kwin/Plasma/6.7] src/backends/drm: backends/drm: release the scanout buffer of virtual layers in beginFrame

Git commit a3e7e71dca0c9c3008d6a309fe96d6e4f0d8ec75 by Xaver Hugl.
Committed on 22/07/2026 at 12:55.
Pushed by zamundaaa into branch 'Plasma/6.7'.

backends/drm: release the scanout buffer of virtual layers in beginFrame

Otherwise we just keep the client buffer until the next scanout cycle, which is
quite broken.

BUG: 523353


(cherry picked from commit 05df3e5199ec6f18386456df51d1675eed66da09)

Co-authored-by: Xaver Hugl <[email protected]>

M  +2    -1    src/backends/drm/drm_virtual_egl_layer.cpp

https://invent.kde.org/plasma/kwin/-/commit/a3e7e71dca0c9c3008d6a309fe96d6e4f0d8ec75

diff --git a/src/backends/drm/drm_virtual_egl_layer.cpp b/src/backends/drm/drm_virtual_egl_layer.cpp
index 729c4d1f78a..0240ae5eb8f 100644
--- a/src/backends/drm/drm_virtual_egl_layer.cpp
+++ b/src/backends/drm/drm_virtual_egl_layer.cpp
@@ -39,7 +39,8 @@ VirtualEglGbmLayer::~VirtualEglGbmLayer()
 
 std::optional<OutputLayerBeginFrameInfo> VirtualEglGbmLayer::doBeginFrame()
 {
-    // gbm surface
+    m_scanoutBuffer.reset();
+
     if (doesGbmSwapchainFit(m_gbmSwapchain.get())) {
         m_oldGbmSwapchain.reset();
         m_oldDamageJournal.clear();