Try to prevent sddm from loading the plugin

kwin/src/breezydesktopeffect.cpp

@@ -113,6 +113,13 @@ namespace KWin
 
 BreezyDesktopEffect::BreezyDesktopEffect()
 {
+    const QByteArray sessionClass = qgetenv("XDG_SESSION_CLASS").toLower();
+    if (sessionClass != "user") {
+        m_sessionClassBlocked = true;
+        qCWarning(KWIN_XR) << "Breezy - effect disabled; expected XDG_SESSION_CLASS=user, got:" << sessionClass;
+        return;
+    }
+
     qCCritical(KWIN_XR) << "\t\t\tBreezy - constructor";
 
     // safe to request on each load, acts as a no-op if already present
@@ -316,12 +323,17 @@ void BreezyDesktopEffect::toggle()
 
 void BreezyDesktopEffect::activate()
 {
+    if (m_sessionClassBlocked) {
+        return;
+    }
     qCCritical(KWIN_XR) << "\t\t\tBreezy - activate";
 
     if (!isRunning()) setRunning(true);
 
     connect(effects, &EffectsHandler::cursorShapeChanged, this, &BreezyDesktopEffect::updateCursorImage);
-    m_cursorUpdateTimer->start();
+    if (m_cursorUpdateTimer) {
+        m_cursorUpdateTimer->start();
+    }
 
     // QuickSceneEffect grabs the keyboard and mouse input, which pulls focus away from the active window
     // and doesn't allow for interaction with anything on the desktop. These two calls fix that.
@@ -331,13 +343,21 @@ void BreezyDesktopEffect::activate()
 
 void BreezyDesktopEffect::deactivate()
 {
+    if (m_sessionClassBlocked) {
+        if (isRunning()) {
+            setRunning(false);
+        }
+        return;
+    }
     qCCritical(KWIN_XR) << "\t\t\tBreezy - deactivate";
 
     m_effectTargetScreenIndex = -1;
     invalidateEffectOnScreenGeometryCache();
 
     disconnect(effects, &EffectsHandler::cursorShapeChanged, this, &BreezyDesktopEffect::updateCursorImage);
-    m_cursorUpdateTimer->stop();
+    if (m_cursorUpdateTimer) {
+        m_cursorUpdateTimer->stop();
+    }
     showCursor();
 
     if (m_removeVirtualDisplaysOnDisable) {
@@ -642,6 +662,9 @@ bool BreezyDesktopEffect::checkParityByte(const char* data) {
 static qint64 lastConfigUpdate = 0;
 static qint64 activatedAt = 0;
 void BreezyDesktopEffect::updatePose() {    
+    if (m_sessionClassBlocked) {
+        return;
+    }
     // Reentrancy guard: if an update is already in progress, skip
     bool expected = false;
     if (!m_poseUpdateInProgress.compare_exchange_strong(expected, true)) {

kwin/src/breezydesktopeffect.h

@@ -189,21 +189,21 @@ namespace KWin
         bool m_zoomOnFocusEnabled = false;
         int m_lookingAtScreenIndex = -1;
         int m_effectTargetScreenIndex = -1;
-        bool m_poseResetState;
+        bool m_poseResetState = false;
         bool m_poseHasPosition = false;
         QList<QQuaternion> m_poseOrientations;
         QVector3D m_posePosition;
-        quint32 m_poseTimeElapsedMs;
+        quint32 m_poseTimeElapsedMs = 0;
         quint64 m_poseTimestamp = 0;
         QList<qreal> m_lookAheadConfig;
         qreal m_lookAheadOverride = -1.0; // -1 = use device default
         QList<quint32> m_displayResolution;
-        qreal m_diagonalFOV;
-        qreal m_lensDistanceRatio;
-        bool m_sbsEnabled;
-        bool m_smoothFollowEnabled;
+        qreal m_diagonalFOV = 0.0;
+        qreal m_lensDistanceRatio = 0.0;
+        bool m_sbsEnabled = false;
+        bool m_smoothFollowEnabled = false;
         QList<QQuaternion> m_smoothFollowOrigin;
-        bool m_customBannerEnabled;
+        bool m_customBannerEnabled = false;
         QFileSystemWatcher *m_shmFileWatcher = nullptr;
         QFileSystemWatcher *m_shmDirectoryWatcher = nullptr;
         bool m_cursorHidden = false;
@@ -211,6 +211,7 @@ namespace KWin
         QTimer *m_cursorUpdateTimer = nullptr;
         QTimer *m_watchdogTimer = nullptr;
         std::atomic<bool> m_poseUpdateInProgress{false};
+        bool m_sessionClassBlocked = false;
         qreal m_focusedDisplayDistance = 0.85;
         qreal m_allDisplaysDistance = 1.05;
         qreal m_displaySpacing = 0.0;

kwin/src/kcm/breezydesktopeffectkcm.cpp

@@ -204,6 +204,15 @@ BreezyDesktopEffectConfig::BreezyDesktopEffectConfig(QObject *parent, const KPlu
     ui.setupUi(widget());
     addConfig(BreezyDesktopConfig::self(), widget());
 
+    // safe to request on each load, acts as a no-op if already present
+    {
+        QJsonObject flags;
+        QJsonArray requested;
+        requested.append(QStringLiteral("productivity_basic"));
+        flags.insert(QStringLiteral("request_features"), requested);
+        XRDriverIPC::instance().writeControlFlags(flags);
+    }
+
     // Advanced tab: measurement units selector (stored as "cm" or "in")
     if (ui.comboMeasurementUnits) {
         ui.comboMeasurementUnits->clear();