diff --git a/abstract_backend.h b/abstract_backend.h
index 8f531cea20..5dfc5d8894 100644
--- a/abstract_backend.h
+++ b/abstract_backend.h
@@ -64,6 +64,9 @@ public:
     void setInitialWindowSize(const QSize &size) {
         m_initialWindowSize = size;
     }
+    void setDeviceIdentifier(const QByteArray &identifier) {
+        m_deviceIdentifier = identifier;
+    }
 
     void pointerMotion(const QPointF &position, quint32 time);
     void pointerButtonPressed(quint32 button, quint32 time);
@@ -99,6 +102,9 @@ protected:
     QSize initialWindowSize() const {
         return m_initialWindowSize;
     }
+    QByteArray deviceIdentifier() const {
+        return m_deviceIdentifier;
+    }
 
 private Q_SLOTS:
     void installThemeCursor(quint32 id, const QPoint &hotspot);
@@ -115,6 +121,7 @@ private:
     bool m_handlesOutputs = false;
     bool m_ready = false;
     QSize m_initialWindowSize;
+    QByteArray m_deviceIdentifier;
 };
 
 }
diff --git a/backends/fbdev/fb_backend.cpp b/backends/fbdev/fb_backend.cpp
index d6426aa49c..e6f2b58676 100644
--- a/backends/fbdev/fb_backend.cpp
+++ b/backends/fbdev/fb_backend.cpp
@@ -81,11 +81,11 @@ void FramebufferBackend::init()
 void FramebufferBackend::openFrameBuffer()
 {
     VirtualTerminal::self()->init();
-    int fd = LogindIntegration::self()->takeDevice(m_device.toUtf8().constData());
+    int fd = LogindIntegration::self()->takeDevice(deviceIdentifier().constData());
     if (fd < 0) {
         qCWarning(KWIN_FB) << "Failed to open frame buffer device through logind, trying without";
     }
-    fd = open(m_device.toUtf8().constData(), O_RDWR | O_CLOEXEC);
+    fd = open(deviceIdentifier().constData(), O_RDWR | O_CLOEXEC);
     if (fd < 0) {
         qCWarning(KWIN_FB) << "failed to open frame buffer device";
         return;
diff --git a/backends/fbdev/fb_backend.h b/backends/fbdev/fb_backend.h
index 81620dd81e..1a6e39c897 100644
--- a/backends/fbdev/fb_backend.h
+++ b/backends/fbdev/fb_backend.h
@@ -38,9 +38,6 @@ public:
     QPainterBackend *createQPainterBackend() override;
 
     void init() override;
-    void setDevice(const QString &device) {
-        m_device = device;
-    }
 
     bool isValid() const {
         return m_fd >= 0;
@@ -72,7 +69,6 @@ public:
 private:
     void openFrameBuffer();
     bool queryScreenInfo();
-    QString m_device = QStringLiteral("/dev/fb0");
     QSize m_resolution;
     QSize m_physicalSize;
     QByteArray m_id;
diff --git a/backends/wayland/wayland_backend.cpp b/backends/wayland/wayland_backend.cpp
index 87d72f2c63..264384857e 100644
--- a/backends/wayland/wayland_backend.cpp
+++ b/backends/wayland/wayland_backend.cpp
@@ -349,7 +349,7 @@ void WaylandCursor::setCursorImage(Qt::CursorShape shape)
 #endif
 }
 
-WaylandBackend::WaylandBackend(const QByteArray &display, QObject *parent)
+WaylandBackend::WaylandBackend(QObject *parent)
     : AbstractBackend(parent)
     , m_display(nullptr)
     , m_eventQueue(new EventQueue(this))
@@ -365,7 +365,6 @@ WaylandBackend::WaylandBackend(const QByteArray &display, QObject *parent)
     , m_fullscreenShell(new FullscreenShell(this))
     , m_subCompositor(new SubCompositor(this))
     , m_cursor(nullptr)
-    , m_displayName(display)
 {
     connect(this, &WaylandBackend::outputsChanged, this, &WaylandBackend::screensQueried);
     connect(this, &WaylandBackend::connectionFailed, this, &WaylandBackend::initFailed);
@@ -440,7 +439,7 @@ void WaylandBackend::init()
         }
     );
     connect(m_registry, &Registry::interfacesAnnounced, this, &WaylandBackend::createSurface);
-    m_connectionThreadObject->setSocketName(m_displayName);
+    m_connectionThreadObject->setSocketName(deviceIdentifier());
     initConnection();
 }
 
diff --git a/backends/wayland/wayland_backend.h b/backends/wayland/wayland_backend.h
index a083cb80d2..fa176d0b62 100644
--- a/backends/wayland/wayland_backend.h
+++ b/backends/wayland/wayland_backend.h
@@ -133,7 +133,7 @@ class KWIN_EXPORT WaylandBackend : public AbstractBackend
 {
     Q_OBJECT
 public:
-    explicit WaylandBackend(const QByteArray &display, QObject *parent = nullptr);
+    explicit WaylandBackend(QObject *parent = nullptr);
     virtual ~WaylandBackend();
     void init() override;
     wl_display *display();
@@ -176,7 +176,6 @@ private:
     KWayland::Client::FullscreenShell *m_fullscreenShell;
     KWayland::Client::SubCompositor *m_subCompositor;
     WaylandCursor *m_cursor;
-    QByteArray m_displayName;
 };
 
 inline
diff --git a/backends/x11/x11windowed_backend.cpp b/backends/x11/x11windowed_backend.cpp
index 029ffb511f..8690258aaa 100644
--- a/backends/x11/x11windowed_backend.cpp
+++ b/backends/x11/x11windowed_backend.cpp
@@ -45,9 +45,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 namespace KWin
 {
 
-X11WindowedBackend::X11WindowedBackend(const QByteArray &display, QObject *parent)
+X11WindowedBackend::X11WindowedBackend(QObject *parent)
     : AbstractBackend(parent)
-    , m_displayName(display)
 {
 }
 
@@ -70,14 +69,14 @@ void X11WindowedBackend::init()
     int screen = 0;
     xcb_connection_t *c = nullptr;
 #if HAVE_X11_XCB
-    Display *xDisplay = XOpenDisplay(m_displayName.constData());
+    Display *xDisplay = XOpenDisplay(deviceIdentifier().constData());
     if (xDisplay) {
         c = XGetXCBConnection(xDisplay);
         XSetEventQueueOwner(xDisplay, XCBOwnsEventQueue);
         screen = XDefaultScreen(xDisplay);
     }
 #else
-    c = xcb_connect(m_displayName.constData(), &screen);
+    c = xcb_connect(deviceIdentifier().constData(), &screen);
 #endif
     if (c && !xcb_connection_has_error(c)) {
         m_connection = c;
diff --git a/backends/x11/x11windowed_backend.h b/backends/x11/x11windowed_backend.h
index 87491435f0..6bb1153b4f 100644
--- a/backends/x11/x11windowed_backend.h
+++ b/backends/x11/x11windowed_backend.h
@@ -39,7 +39,7 @@ class KWIN_EXPORT X11WindowedBackend : public AbstractBackend
     Q_OBJECT
     Q_PROPERTY(QSize size READ size NOTIFY sizeChanged)
 public:
-    X11WindowedBackend(const QByteArray &display, QObject *parent);
+    X11WindowedBackend(QObject *parent);
     virtual ~X11WindowedBackend();
     void init() override;
 
@@ -79,7 +79,6 @@ private:
     void handleExpose(xcb_expose_event_t *event);
     void updateSize(xcb_configure_notify_event_t *event);
 
-    QByteArray m_displayName;
     xcb_connection_t *m_connection = nullptr;
     xcb_screen_t *m_screen = nullptr;
     int m_screenNumber = 0;
diff --git a/main_wayland.cpp b/main_wayland.cpp
index f03366a50a..5580e251b6 100644
--- a/main_wayland.cpp
+++ b/main_wayland.cpp
@@ -101,11 +101,13 @@ void ApplicationWayland::createBackend()
     AbstractBackend *backend = nullptr;
     if (m_windowed) {
         if (!m_waylandDisplay.isEmpty()) {
-            Wayland::WaylandBackend *b = new Wayland::WaylandBackend(m_waylandDisplay, this);
+            Wayland::WaylandBackend *b = new Wayland::WaylandBackend(this);
+            b->setDeviceIdentifier(m_waylandDisplay);
             backend = b;
         }
         if (!backend && !m_x11Display.isEmpty()) {
-            KWin::X11WindowedBackend *x11Backend = new KWin::X11WindowedBackend(m_x11Display, this);
+            KWin::X11WindowedBackend *x11Backend = new KWin::X11WindowedBackend(this);
+            x11Backend->setDeviceIdentifier(m_x11Display);
             backend = x11Backend;
         }
     }
@@ -117,7 +119,7 @@ void ApplicationWayland::createBackend()
 #endif
     if (!m_framebuffer.isEmpty()) {
         FramebufferBackend *b = new FramebufferBackend(this);
-        b->setDevice(m_framebuffer);
+        b->setDeviceIdentifier(m_framebuffer.toUtf8());
         backend = b;
     }