diff --git a/src/backends/drm/drm_lease_egl_gbm_layer.cpp b/src/backends/drm/drm_lease_egl_gbm_layer.cpp
index 85653a0a94..112fb4ba16 100644
--- a/src/backends/drm/drm_lease_egl_gbm_layer.cpp
+++ b/src/backends/drm/drm_lease_egl_gbm_layer.cpp
@@ -30,7 +30,7 @@ DrmLeaseEglGbmLayer::DrmLeaseEglGbmLayer(EglGbmBackend *backend, DrmPipeline *pi
 QSharedPointer<DrmBuffer> DrmLeaseEglGbmLayer::testBuffer()
 {
     const auto mods = m_pipeline->formats().value(DRM_FORMAT_XRGB8888);
-    const auto size = m_pipeline->sourceSize();
+    const auto size = m_pipeline->bufferSize();
     if (!m_buffer || m_buffer->size() != size || !(mods.isEmpty() || mods.contains(m_buffer->modifier()))) {
         gbm_bo *newBo;
         if (mods.isEmpty()) {
diff --git a/src/backends/drm/drm_pipeline.cpp b/src/backends/drm/drm_pipeline.cpp
index 045c6a3a2c..4fdf1a0016 100644
--- a/src/backends/drm/drm_pipeline.cpp
+++ b/src/backends/drm/drm_pipeline.cpp
@@ -368,15 +368,6 @@ QSize DrmPipeline::bufferSize() const
     return modeSize;
 }
 
-QSize DrmPipeline::sourceSize() const
-{
-    const auto modeSize = pending.mode->size();
-    if (pending.sourceTransformation & (DrmPlane::Transformation::Rotate90 | DrmPlane::Transformation::Rotate270)) {
-        return modeSize.transposed();
-    }
-    return modeSize;
-}
-
 bool DrmPipeline::isCursorVisible() const
 {
     const QRect mode = QRect(QPoint(), pending.mode->size());
diff --git a/src/backends/drm/drm_pipeline.h b/src/backends/drm/drm_pipeline.h
index 8564b28efa..12c21d9133 100644
--- a/src/backends/drm/drm_pipeline.h
+++ b/src/backends/drm/drm_pipeline.h
@@ -79,10 +79,6 @@ public:
     bool modesetPresentPending() const;
     void resetModesetPresentPending();
     void printDebugInfo() const;
-    /**
-     * which size buffers for rendering should have
-     */
-    QSize sourceSize() const;
     /**
      * what size buffers submitted to this pipeline should have
      */
diff --git a/src/backends/drm/drm_qpainter_layer.cpp b/src/backends/drm/drm_qpainter_layer.cpp
index 2465aa0ba9..55da331f3b 100644
--- a/src/backends/drm/drm_qpainter_layer.cpp
+++ b/src/backends/drm/drm_qpainter_layer.cpp
@@ -33,7 +33,7 @@ DrmQPainterLayer::DrmQPainterLayer(DrmQPainterBackend *backend, DrmPipeline *pip
 OutputLayerBeginFrameInfo DrmQPainterLayer::beginFrame()
 {
     if (!doesSwapchainFit()) {
-        m_swapchain = QSharedPointer<DumbSwapchain>::create(m_pipeline->gpu(), m_pipeline->sourceSize(), DRM_FORMAT_XRGB8888);
+        m_swapchain = QSharedPointer<DumbSwapchain>::create(m_pipeline->gpu(), m_pipeline->bufferSize(), DRM_FORMAT_XRGB8888);
     }
     QRegion needsRepaint;
     if (!m_swapchain->acquireBuffer(&needsRepaint)) {
@@ -55,14 +55,14 @@ void DrmQPainterLayer::endFrame(const QRegion &renderedRegion, const QRegion &da
 QSharedPointer<DrmBuffer> DrmQPainterLayer::testBuffer()
 {
     if (!doesSwapchainFit()) {
-        m_swapchain = QSharedPointer<DumbSwapchain>::create(m_pipeline->gpu(), m_pipeline->sourceSize(), DRM_FORMAT_XRGB8888);
+        m_swapchain = QSharedPointer<DumbSwapchain>::create(m_pipeline->gpu(), m_pipeline->bufferSize(), DRM_FORMAT_XRGB8888);
     }
     return m_swapchain->currentBuffer();
 }
 
 bool DrmQPainterLayer::doesSwapchainFit() const
 {
-    return m_swapchain && m_swapchain->size() == m_pipeline->sourceSize();
+    return m_swapchain && m_swapchain->size() == m_pipeline->bufferSize();
 }
 
 QSharedPointer<DrmBuffer> DrmQPainterLayer::currentBuffer() const
@@ -112,7 +112,7 @@ DrmLeaseQPainterLayer::DrmLeaseQPainterLayer(DrmQPainterBackend *backend, DrmPip
 
 QSharedPointer<DrmBuffer> DrmLeaseQPainterLayer::testBuffer()
 {
-    const auto size = m_pipeline->sourceSize();
+    const auto size = m_pipeline->bufferSize();
     if (!m_buffer || m_buffer->size() != size) {
         m_buffer = QSharedPointer<DrmDumbBuffer>::create(m_pipeline->gpu(), size, DRM_FORMAT_XRGB8888);
     }
diff --git a/src/backends/drm/egl_gbm_layer.cpp b/src/backends/drm/egl_gbm_layer.cpp
index 3bb623bafa..1f4d7e34f5 100644
--- a/src/backends/drm/egl_gbm_layer.cpp
+++ b/src/backends/drm/egl_gbm_layer.cpp
@@ -64,7 +64,7 @@ void EglGbmLayer::aboutToStartPainting(const QRegion &damagedRegion)
 void EglGbmLayer::endFrame(const QRegion &renderedRegion, const QRegion &damagedRegion)
 {
     Q_UNUSED(renderedRegion)
-    const auto ret = m_surface.endRendering(m_pipeline->pending.bufferTransformation, damagedRegion);
+    const auto ret = m_surface.endRendering(m_pipeline->pending.sourceTransformation, damagedRegion);
     if (ret.has_value()) {
         std::tie(m_currentBuffer, m_currentDamage) = ret.value();
     }
@@ -77,7 +77,7 @@ QRegion EglGbmLayer::currentDamage() const
 
 QSharedPointer<DrmBuffer> EglGbmLayer::testBuffer()
 {
-    if (!m_surface.doesSurfaceFit(m_pipeline->sourceSize(), m_pipeline->formats())) {
+    if (!m_surface.doesSurfaceFit(m_pipeline->bufferSize(), m_pipeline->formats())) {
         renderTestBuffer();
     }
     return m_currentBuffer;
@@ -115,7 +115,7 @@ bool EglGbmLayer::scanout(SurfaceItem *surfaceItem)
     }
     const auto surface = item->surface();
     const auto buffer = qobject_cast<KWaylandServer::LinuxDmaBufV1ClientBuffer *>(surface->buffer());
-    if (!buffer || buffer->planes().isEmpty() || buffer->size() != m_pipeline->sourceSize()) {
+    if (!buffer || buffer->planes().isEmpty() || buffer->size() != m_pipeline->bufferSize()) {
         return false;
     }