1 files changed, 36 insertions, 23 deletions
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
index 0fd0bffbbc..ff18b43a3d 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
@@ -1,14 +1,13 @@
 /****************************************************************************
 **
 ** Copyright (C) 2015 Pier Luigi Fiorini <pierluigi.fiorini@gmail.com>
-** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2016 The Qt Company Ltd.
 ** Copyright (C) 2016 Pelagicore AG
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the plugins of the Qt Toolkit.
 **
-** $QT_BEGIN_LICENSE:COMM$
-**
+** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
@@ -17,25 +16,26 @@
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
-** $QT_END_LICENSE$
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
-**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
 **
+** $QT_END_LICENSE$
 **
 ****************************************************************************/
 
@@ -83,7 +83,13 @@ bool QEglFSKmsGbmDevice::open()
 
     setFd(fd);
 
-    m_eventReader.create(this);
+    if (usesEventReader()) {
+        qCDebug(qLcEglfsKmsDebug, "Using dedicated drm event reading thread");
+        m_eventReader.create(this);
+    } else {
+        qCDebug(qLcEglfsKmsDebug, "Not using dedicated drm event reading thread; "
+                "threaded multi-screen setups may experience problems");
+    }
 
     return true;
 }
@@ -92,7 +98,8 @@ void QEglFSKmsGbmDevice::close()
 {
     // Note: screens are gone at this stage.
 
-    m_eventReader.destroy();
+    if (usesEventReader())
+        m_eventReader.destroy();
 
     if (m_gbm_device) {
         gbm_device_destroy(m_gbm_device);
@@ -169,4 +176,10 @@ void QEglFSKmsGbmDevice::registerScreen(QPlatformScreen *screen,
         m_globalCursor->reevaluateVisibilityForScreens();
 }
 
+bool QEglFSKmsGbmDevice::usesEventReader() const
+{
+    static const bool eventReaderThreadDisabled = qEnvironmentVariableIntValue("QT_QPA_EGLFS_KMS_NO_EVENT_READER_THREAD");
+    return !eventReaderThreadDisabled;
+}
+
 QT_END_NAMESPACE