From f70be829c6fd957132a45624c5d7e824c379b069 Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Fri, 31 Mar 2023 01:22:48 +0200
Subject: [PATCH] backends/drm: don't access nullptr output configs

---
 src/backends/drm/drm_backend.cpp | 10 +++++++---
 src/backends/drm/drm_output.cpp  |  7 ++-----
 src/backends/drm/drm_output.h    |  5 +++--
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/src/backends/drm/drm_backend.cpp b/src/backends/drm/drm_backend.cpp
index c52844185f..b88edf7096 100644
--- a/src/backends/drm/drm_backend.cpp
+++ b/src/backends/drm/drm_backend.cpp
@@ -474,7 +474,7 @@ bool DrmBackend::applyOutputChanges(const OutputConfiguration &config)
                 continue;
             }
             if (const auto changeset = config.constChangeSet(output)) {
-                output->queueChanges(config);
+                output->queueChanges(changeset);
                 if (changeset->enabled) {
                     toBeEnabled << output;
                 } else {
@@ -495,10 +495,14 @@ bool DrmBackend::applyOutputChanges(const OutputConfiguration &config)
     // first, apply changes to drm outputs.
     // This may remove the placeholder output and thus change m_outputs!
     for (const auto &output : std::as_const(toBeEnabled)) {
-        output->applyQueuedChanges(config);
+        if (const auto changeset = config.constChangeSet(output)) {
+            output->applyQueuedChanges(changeset);
+        }
     }
     for (const auto &output : std::as_const(toBeDisabled)) {
-        output->applyQueuedChanges(config);
+        if (const auto changeset = config.constChangeSet(output)) {
+            output->applyQueuedChanges(changeset);
+        }
     }
     // only then apply changes to the virtual outputs
     for (const auto &gpu : std::as_const(m_gpus)) {
diff --git a/src/backends/drm/drm_output.cpp b/src/backends/drm/drm_output.cpp
index fa7d41ed48..c9c5328c2f 100644
--- a/src/backends/drm/drm_output.cpp
+++ b/src/backends/drm/drm_output.cpp
@@ -398,12 +398,11 @@ DrmPipeline *DrmOutput::pipeline() const
     return m_pipeline;
 }
 
-bool DrmOutput::queueChanges(const OutputConfiguration &config)
+bool DrmOutput::queueChanges(const std::shared_ptr<OutputChangeSet> &props)
 {
     static bool valid;
     static int envOnlySoftwareRotations = qEnvironmentVariableIntValue("KWIN_DRM_SW_ROTATIONS_ONLY", &valid) == 1 || !valid;
 
-    const auto props = config.constChangeSet(this);
     const auto mode = props->mode.value_or(currentMode()).lock();
     if (!mode) {
         return false;
@@ -419,7 +418,7 @@ bool DrmOutput::queueChanges(const OutputConfiguration &config)
     return true;
 }
 
-void DrmOutput::applyQueuedChanges(const OutputConfiguration &config)
+void DrmOutput::applyQueuedChanges(const std::shared_ptr<OutputChangeSet> &props)
 {
     if (!m_connector->isConnected()) {
         return;
@@ -427,8 +426,6 @@ void DrmOutput::applyQueuedChanges(const OutputConfiguration &config)
     Q_EMIT aboutToChange();
     m_pipeline->applyPendingChanges();
 
-    auto props = config.constChangeSet(this);
-
     State next = m_state;
     next.enabled = props->enabled && m_pipeline->crtc();
     next.position = props->pos.value_or(m_state.position);
diff --git a/src/backends/drm/drm_output.h b/src/backends/drm/drm_output.h
index 57eb0f2480..07606c556d 100644
--- a/src/backends/drm/drm_output.h
+++ b/src/backends/drm/drm_output.h
@@ -29,6 +29,7 @@ class DrmGpu;
 class DrmPipeline;
 class DumbSwapchain;
 class DrmLease;
+class OutputChangeSet;
 
 class KWIN_EXPORT DrmOutput : public DrmAbstractOutput
 {
@@ -44,8 +45,8 @@ public:
     DrmOutputLayer *primaryLayer() const override;
     DrmOutputLayer *cursorLayer() const override;
 
-    bool queueChanges(const OutputConfiguration &config);
-    void applyQueuedChanges(const OutputConfiguration &config);
+    bool queueChanges(const std::shared_ptr<OutputChangeSet> &properties);
+    void applyQueuedChanges(const std::shared_ptr<OutputChangeSet> &properties);
     void revertQueuedChanges();
     void updateModes();
     void updateDpmsMode(DpmsMode dpmsMode);