fix wrong cursor hotspot under Wayland on VMs

src/plugins/platforms/drm/drm_output.cpp

@@ -103,7 +103,8 @@ bool DrmOutput::hideCursor()
 bool DrmOutput::showCursor()
 {
     bool visibleBefore = m_pipeline->isCursorVisible();
-    if (m_pipeline->setCursor(m_cursor)) {
+    const Cursor * const cursor = Cursors::self()->currentCursor();
+    if (m_pipeline->setCursor(m_cursor, logicalToNativeMatrix(cursor->rect(), scale(), transform()).map(cursor->hotspot()) )) {
         if (RenderLoopPrivate::get(m_renderLoop)->presentMode == RenderLoopPrivate::SyncMode::Adaptive
             && !visibleBefore
             && m_pipeline->isCursorVisible()) {
@@ -149,7 +150,7 @@ bool DrmOutput::updateCursor()
     p.setWorldTransform(logicalToNativeMatrix(cursor->rect(), 1, transform()).toTransform());
     p.drawImage(QPoint(0, 0), cursorImage);
     p.end();
-    if (m_pipeline->setCursor(m_cursor)) {
+    if (m_pipeline->setCursor(m_cursor, logicalToNativeMatrix(cursor->rect(), scale(), transform()).map(cursor->hotspot()) )) {
         if (RenderLoopPrivate::get(m_renderLoop)->presentMode == RenderLoopPrivate::SyncMode::Adaptive
             && m_pipeline->isCursorVisible()) {
             m_renderLoop->scheduleRepaint();

src/plugins/platforms/drm/drm_pipeline.cpp

@@ -305,18 +305,24 @@ bool DrmPipeline::checkTestBuffer()
     return false;
 }
 
-bool DrmPipeline::setCursor(const QSharedPointer<DrmDumbBuffer> &buffer)
+bool DrmPipeline::setCursor(const QSharedPointer<DrmDumbBuffer> &buffer, const QPoint &hotspot)
 {
-    if (!m_cursor.dirty && m_cursor.buffer == buffer) {
+    if (!m_cursor.dirty && m_cursor.buffer == buffer && m_cursor.hotspot == hotspot) {
         return true;
     }
     const QSize &s = buffer ? buffer->size() : QSize(64, 64);
-    if (drmModeSetCursor(m_gpu->fd(), m_crtc->id(), buffer ? buffer->handle() : 0, s.width(), s.height()) != 0) {
+    int ret = drmModeSetCursor2(m_gpu->fd(), m_crtc->id(), buffer ? buffer->handle() : 0, s.width(), s.height(), hotspot.x(), hotspot.y());
+    if (ret == ENOTSUP) {
+        // for NVIDIA case that does not support drmModeSetCursor2
+        ret = drmModeSetCursor(m_gpu->fd(), m_crtc->id(), buffer ? buffer->handle() : 0, s.width(), s.height());
+    }
+    if (ret != 0) {
         qCWarning(KWIN_DRM) << "Could not set cursor:" << strerror(errno);
         return false;
     }
     m_cursor.buffer = buffer;
     m_cursor.dirty = false;
+    m_cursor.hotspot = hotspot;
     return true;
 }
 
@@ -374,7 +380,7 @@ bool DrmPipeline::setActive(bool active)
     }
     if (m_active) {
         // enable cursor (again)
-        setCursor(m_cursor.buffer);
+        setCursor(m_cursor.buffer, m_cursor.hotspot);
     }
     return success;
 }

src/plugins/platforms/drm/drm_pipeline.h

@@ -54,7 +54,7 @@ public:
     bool test(const QVector<DrmPipeline*> &pipelines);
 
     bool modeset(int modeIndex);
-    bool setCursor(const QSharedPointer<DrmDumbBuffer> &buffer);
+    bool setCursor(const QSharedPointer<DrmDumbBuffer> &buffer, const QPoint &hotspot = QPoint());
     bool setActive(bool enable);
     bool setGammaRamp(const GammaRamp &ramp);
     bool setTransformation(const DrmPlane::Transformations &transform);
@@ -103,6 +103,7 @@ private:
     bool m_legacyNeedsModeset = true;
     struct {
         QPoint pos = QPoint(100, 100);
+        QPoint hotspot;
         QSharedPointer<DrmDumbBuffer> buffer;
         bool dirty = true;// we don't know what the current state is
     } m_cursor;