From 33fad70c9bf496ef25947cb216d233c57b5a181e Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Fri, 16 Oct 2020 16:11:23 +0300
Subject: [PATCH] platforms/drm: Fix initialization of EGL displays

Currently, every time compositing is restarted, both the gbm and the egl
streams backend will re-obtain the EGLDisplay object.

This is wrong because the core assumption is that the EGL display doesn't
change once it has been obtained.
---
 plugins/platforms/drm/drm_gpu.h              | 12 ++++++++++++
 plugins/platforms/drm/egl_gbm_backend.cpp    |  3 ++-
 plugins/platforms/drm/egl_stream_backend.cpp |  3 ++-
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/plugins/platforms/drm/drm_gpu.h b/plugins/platforms/drm/drm_gpu.h
index 21dec50644..29cad2b1d9 100644
--- a/plugins/platforms/drm/drm_gpu.h
+++ b/plugins/platforms/drm/drm_gpu.h
@@ -13,6 +13,9 @@
 #include <qobject.h>
 #include <QVector>
 
+#include <epoxy/egl.h>
+#include <fixx11h.h>
+
 #include "drm_buffer.h"
 
 struct gbm_device;
@@ -58,6 +61,10 @@ public:
     gbm_device *gbmDevice() const {
         return m_gbmDevice;
     }
+
+    EGLDisplay eglDisplay() const {
+        return m_eglDisplay;
+    }
     
     QVector<DrmPlane*> planes() const {
         return m_planes;
@@ -66,6 +73,10 @@ public:
     void setGbmDevice(gbm_device *d) {
         m_gbmDevice = d;
     }
+
+    void setEglDisplay(EGLDisplay display) {
+        m_eglDisplay = display;
+    }
     
     DrmDumbBuffer *createBuffer(const QSize &size) const {
         return new DrmDumbBuffer(m_fd, size);
@@ -95,6 +106,7 @@ private:
     bool m_atomicModeSetting;
     bool m_useEglStreams;
     gbm_device* m_gbmDevice;
+    EGLDisplay m_eglDisplay = EGL_NO_DISPLAY;
     
 // all available planes: primarys, cursors and overlays
     QVector<DrmPlane*> m_planes;
diff --git a/plugins/platforms/drm/egl_gbm_backend.cpp b/plugins/platforms/drm/egl_gbm_backend.cpp
index 6188f5f3f6..8074e4431c 100644
--- a/plugins/platforms/drm/egl_gbm_backend.cpp
+++ b/plugins/platforms/drm/egl_gbm_backend.cpp
@@ -74,7 +74,7 @@ void EglGbmBackend::cleanupOutput(Output &output)
 bool EglGbmBackend::initializeEgl()
 {
     initClientExtensions();
-    EGLDisplay display = eglDisplay();
+    EGLDisplay display = m_gpu->eglDisplay();
 
     // Use eglGetPlatformDisplayEXT() to get the display pointer
     // if the implementation supports it.
@@ -98,6 +98,7 @@ bool EglGbmBackend::initializeEgl()
         m_gpu->setGbmDevice(device);
 
         display = eglGetPlatformDisplayEXT(platform, device, nullptr);
+        m_gpu->setEglDisplay(display);
     }
 
     if (display == EGL_NO_DISPLAY) {
diff --git a/plugins/platforms/drm/egl_stream_backend.cpp b/plugins/platforms/drm/egl_stream_backend.cpp
index a166fb962b..ab6d25c21f 100644
--- a/plugins/platforms/drm/egl_stream_backend.cpp
+++ b/plugins/platforms/drm/egl_stream_backend.cpp
@@ -121,7 +121,7 @@ void EglStreamBackend::cleanupOutput(const Output &o)
 bool EglStreamBackend::initializeEgl()
 {
     initClientExtensions();
-    EGLDisplay display = eglDisplay();
+    EGLDisplay display = m_gpu->eglDisplay();
     if (display == EGL_NO_DISPLAY) {
         if (!hasClientExtension(QByteArrayLiteral("EGL_EXT_device_base")) &&
             !(hasClientExtension(QByteArrayLiteral("EGL_EXT_device_query")) &&
@@ -157,6 +157,7 @@ bool EglStreamBackend::initializeEgl()
             display = eglGetPlatformDisplayEXT(EGL_PLATFORM_DEVICE_EXT, device, platformAttribs);
             break;
         }
+        m_gpu->setEglDisplay(display);
     }
 
     if (display == EGL_NO_DISPLAY) {