From 97f8bfac5c21e730a381a63d371c159eabc45daf Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Fri, 16 Jul 2021 17:17:19 +0200
Subject: [PATCH] platforms/drm: where necessary, disconnect CRTCs after VT
 switch

---
 src/plugins/platforms/drm/drm_backend.cpp  |  6 ++++++
 src/plugins/platforms/drm/drm_pipeline.cpp | 10 ++++++++++
 src/plugins/platforms/drm/drm_pipeline.h   |  6 ++++++
 3 files changed, 22 insertions(+)

diff --git a/src/plugins/platforms/drm/drm_backend.cpp b/src/plugins/platforms/drm/drm_backend.cpp
index bf77a5cfa2..b37e973477 100644
--- a/src/plugins/platforms/drm/drm_backend.cpp
+++ b/src/plugins/platforms/drm/drm_backend.cpp
@@ -144,12 +144,18 @@ void DrmBackend::reactivate()
     for (const auto &output : qAsConst(m_outputs)) {
         output->pipeline()->updateProperties();
         if (output->isEnabled()) {
+            if (output->gpu()->atomicModeSetting() && !output->pipeline()->isConnected()) {
+                output->pipeline()->setActive(false);
+            }
             output->renderLoop()->uninhibit();
             output->showCursor();
         } else {
             output->pipeline()->setActive(false);
         }
     }
+    for (const auto &output : qAsConst(m_outputs)) {
+        output->pipeline()->setActive(output->isEnabled());
+    }
 
     if (Compositor *compositor = Compositor::self()) {
         compositor->addRepaintFull();
diff --git a/src/plugins/platforms/drm/drm_pipeline.cpp b/src/plugins/platforms/drm/drm_pipeline.cpp
index 5ce6f9f04b..45903b9c42 100644
--- a/src/plugins/platforms/drm/drm_pipeline.cpp
+++ b/src/plugins/platforms/drm/drm_pipeline.cpp
@@ -530,6 +530,16 @@ void DrmPipeline::updateProperties()
     m_cursor.dirty = true;
 }
 
+bool DrmPipeline::isConnected() const
+{
+    if (m_primaryPlane) {
+        return m_connector->getProp(DrmConnector::PropertyIndex::CrtcId)->current() == m_crtc->id()
+            && m_primaryPlane->getProp(DrmPlane::PropertyIndex::CrtcId)->current() == m_crtc->id();
+    } else {
+        return false;
+    }
+}
+
 static void printProps(DrmObject *object)
 {
     auto list = object->properties();
diff --git a/src/plugins/platforms/drm/drm_pipeline.h b/src/plugins/platforms/drm/drm_pipeline.h
index 03bcdd4f26..d49695a561 100644
--- a/src/plugins/platforms/drm/drm_pipeline.h
+++ b/src/plugins/platforms/drm/drm_pipeline.h
@@ -35,6 +35,12 @@ public:
     DrmPipeline(DrmGpu *gpu, DrmConnector *conn, DrmCrtc *crtc, DrmPlane *primaryPlane);
     ~DrmPipeline();
 
+    /**
+     * checks if the connector(s) and plane(s) are set to the CRTC(s)
+     * always returns false in legacy mode
+     */
+    bool isConnected() const;
+
     /**
      * tests the pending commit first and commits it if the test passes
      * if the test fails, there is a guarantee for no lasting changes