Recommended backport from 6.8.0 to prevent a crash with kcm_pulseaudio.
https://bugreports.qt.io/browse/QTBUG-129165
https://bugs.kde.org/show_bug.cgi?id=493266
(kde bug mentions is for 6.8.0, but was seemingly the -rc without the fix)
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -11,4 +11,5 @@
 
 Q_LOGGING_CATEGORY(lcItemViewDelegateLifecycle, "qt.quick.itemview.lifecycle")
+Q_LOGGING_CATEGORY(lcCount, "qt.quick.itemview.count")
 
 // Default cacheBuffer for all views.
@@ -224,5 +225,5 @@
         if (QQmlDelegateModel *dataModel = qobject_cast<QQmlDelegateModel*>(d->model))
             QObjectPrivate::connect(dataModel, &QQmlDelegateModel::delegateChanged, d, &QQuickItemViewPrivate::applyDelegateChange);
-        emit countChanged();
+        d->emitCountChanged();
     }
     emit modelChanged();
@@ -256,5 +257,5 @@
         dataModel->setDelegate(delegate);
         if (oldCount != dataModel->count())
-            emit countChanged();
+            d->emitCountChanged();
     }
     emit delegateChanged();
@@ -1126,4 +1127,12 @@
 }
 
+// Simplifies debugging of count.
+void QQuickItemViewPrivate::emitCountChanged()
+{
+    Q_Q(QQuickItemView);
+    qCDebug(lcCount).nospace() << "about to emit countChanged for " << q << "; count changed to " << q->count();
+    emit q->countChanged();
+}
+
 void QQuickItemViewPrivate::itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change,
                                                 const QRectF &oldGeometry)
@@ -1225,5 +1234,5 @@
         }
         d->moveReason = QQuickItemViewPrivate::Other;
-        emit countChanged();
+        d->emitCountChanged();
 #if QT_CONFIG(quick_viewtransitions)
         if (d->transitioner && d->transitioner->populateTransition)
@@ -1488,5 +1497,5 @@
     }
     if (d->model && d->model->count())
-        emit countChanged();
+        d->emitCountChanged();
 }
 
@@ -1814,5 +1823,5 @@
 
         if (prevCount != itemCount)
-            emit q->countChanged();
+            emitCountChanged();
     } while (currentChanges.hasPendingChanges() || bufferedChanges.hasPendingChanges());
     storeFirstVisibleItemPosition();
@@ -1865,4 +1874,14 @@
     // views (see tst_QQuickListView::resizeView).
     if ((!isValid() && !visibleItems.size()) || q->size().isNull()) {
+        if (q->size().isNull() && hasPendingChanges()) {
+            // count() refers to the number of items in the model, not in the view
+            // (which is why we don't emit for the !visibleItems.size() case).
+            // If there are pending model changes, emit countChanged in order to
+            // support the use case of QTBUG-129165, where visible is bound to count > 0
+            // and the ListView is in a layout with Layout.preferredHeight bound to
+            // contentHeight. This ensures that a hidden ListView will become visible.
+            emitCountChanged();
+        }
+
         clear();
         setPosition(contentStartOffset());
@@ -2139,5 +2158,5 @@
     updateSections();
     if (prevItemCount != itemCount)
-        emit q->countChanged();
+        emitCountChanged();
     if (!visibleAffected && viewportChanged)
         updateViewport();
--- a/src/quick/items/qquickitemview_p_p.h
+++ b/src/quick/items/qquickitemview_p_p.h
@@ -230,4 +230,6 @@
     }
 
+    void emitCountChanged();
+
     virtual QQuickItemViewAttached *getAttachedObject(const QObject *) const { return nullptr; }
 
--- a/tests/auto/quick/qquicklistview2/data/visibleBoundToCountGreaterThanZero.qml
+++ b/tests/auto/quick/qquicklistview2/data/visibleBoundToCountGreaterThanZero.qml
@@ -0,0 +1,31 @@
+import QtQuick
+import QtQuick.Layouts
+
+ColumnLayout {
+    property alias listView: listView
+
+    ListView {
+        id: listView
+
+        visible: count > 0 // actual defect. countChanged never fires so this never turns true
+
+        Layout.fillWidth: true
+        Layout.preferredHeight: contentHeight // grow with content, initially 0
+
+        model: ListModel {
+            id: idModel
+        }
+
+        delegate: Text {
+            required property string name
+            text: name
+        }
+
+        Timer {
+            running: true
+            interval: 10
+            repeat: true
+            onTriggered: idModel.append({name:"Hello"})
+        }
+    }
+}
--- a/tests/auto/quick/qquicklistview2/tst_qquicklistview2.cpp
+++ b/tests/auto/quick/qquicklistview2/tst_qquicklistview2.cpp
@@ -19,4 +19,6 @@
 using namespace QQuickVisualTestUtils;
 
+static const int oneSecondInMs = 1000;
+
 class tst_QQuickListView2 : public QQmlDataTest
 {
@@ -69,4 +71,5 @@
 
     void clearObjectListModel();
+    void visibleBoundToCountGreaterThanZero();
 
 private:
@@ -1313,4 +1316,21 @@
 }
 
+void tst_QQuickListView2::visibleBoundToCountGreaterThanZero()
+{
+    QQuickView window;
+    QVERIFY(QQuickTest::showView(window, testFileUrl("visibleBoundToCountGreaterThanZero.qml")));
+
+    auto *listView = window.rootObject()->property("listView").value<QQuickListView *>();
+    QVERIFY(listView);
+
+    QSignalSpy countChangedSpy(listView, SIGNAL(countChanged()));
+    QVERIFY(countChangedSpy.isValid());
+
+    QTRY_COMPARE_GT_WITH_TIMEOUT(listView->count(), 1, oneSecondInMs);
+    // Using the TRY variant here as well is necessary.
+    QTRY_COMPARE_GT_WITH_TIMEOUT(countChangedSpy.count(), 1, oneSecondInMs);
+    QVERIFY(listView->isVisible());
+}
+
 QTEST_MAIN(tst_QQuickListView2)