From c952c3a3aee81dc2b0879a28f90dabeb8b751b80 Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Sat, 22 Jan 2022 15:07:41 +0100
Subject: [PATCH] backends/drm: add environment variable
 KWIN_DRM_NO_DIRECT_SCANOUT

Can be useful for debugging
---
 src/backends/drm/egl_gbm_backend.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/backends/drm/egl_gbm_backend.cpp b/src/backends/drm/egl_gbm_backend.cpp
index c159281ad2..e81c369bda 100644
--- a/src/backends/drm/egl_gbm_backend.cpp
+++ b/src/backends/drm/egl_gbm_backend.cpp
@@ -633,6 +633,11 @@ void EglGbmBackend::updateBufferAge(Output &output, const QRegion &dirty)
 
 bool EglGbmBackend::scanout(AbstractOutput *drmOutput, SurfaceItem *surfaceItem)
 {
+    static bool valid;
+    static const bool directScanoutDisabled = qEnvironmentVariableIntValue("KWIN_DRM_NO_DIRECT_SCANOUT", &valid) == 1 && valid;
+    if (directScanoutDisabled) {
+        return false;
+    }
     Q_ASSERT(m_outputs.contains(drmOutput));
     SurfaceItemWayland *item = qobject_cast<SurfaceItemWayland *>(surfaceItem);
     if (!item) {