From 2fff5891a51ed5b2a62a5f36865298f495ce780e Mon Sep 17 00:00:00 2001
From: Xaver Hugl <xaver.hugl@gmail.com>
Date: Mon, 31 Jul 2023 14:26:25 +0200
Subject: [PATCH] backends/drm: wait for pending pageflips before turning
 outputs off

---
 src/backends/drm/drm_gpu.h      | 2 +-
 src/backends/drm/drm_output.cpp | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/backends/drm/drm_gpu.h b/src/backends/drm/drm_gpu.h
index 9bdf23639a..2e89d5d929 100644
--- a/src/backends/drm/drm_gpu.h
+++ b/src/backends/drm/drm_gpu.h
@@ -112,6 +112,7 @@ public:
 
     FileDescriptor createNonMasterFd() const;
     std::unique_ptr<DrmLease> leaseOutputs(const QVector<DrmOutput *> &outputs);
+    void waitIdle();
 
 Q_SIGNALS:
     void activeChanged(bool active);
@@ -123,7 +124,6 @@ private:
     DrmOutput *findOutput(quint32 connector);
     void removeOutput(DrmOutput *output);
     void initDrmResources();
-    void waitIdle();
 
     DrmPipeline::Error checkCrtcAssignment(QVector<DrmConnector *> connectors, const QVector<DrmCrtc *> &crtcs);
     DrmPipeline::Error testPipelines();
diff --git a/src/backends/drm/drm_output.cpp b/src/backends/drm/drm_output.cpp
index 747ea49e4a..7630a4dad6 100644
--- a/src/backends/drm/drm_output.cpp
+++ b/src/backends/drm/drm_output.cpp
@@ -272,6 +272,9 @@ bool DrmOutput::setDrmDpmsMode(DpmsMode mode)
         updateDpmsMode(mode);
         return true;
     }
+    if (!active) {
+        gpu()->waitIdle();
+    }
     m_pipeline->setActive(active);
     if (DrmPipeline::commitPipelines({m_pipeline}, active ? DrmPipeline::CommitMode::TestAllowModeset : DrmPipeline::CommitMode::CommitModeset) == DrmPipeline::Error::None) {
         m_pipeline->applyPendingChanges();