1 files changed, 16 insertions, 4 deletions
diff --git a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
index 6d903a3f1e..a7592ed55e 100644
--- a/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
+++ b/src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp
@@ -7,6 +7,7 @@
 #include "qeglfskmsgbmscreen_p.h"
 
 #include <private/qeglfsintegration_p.h>
+#include <private/qeglfskmsintegration_p.h>
 
 #include <QtCore/QLoggingCategory>
 #include <QtCore/private/qcore_unix_p.h>
@@ -15,8 +16,6 @@
 
 QT_BEGIN_NAMESPACE
 
-Q_DECLARE_LOGGING_CATEGORY(qLcEglfsKmsDebug)
-
 QEglFSKmsGbmDevice::QEglFSKmsGbmDevice(QKmsScreenConfig *screenConfig, const QString &path)
     : QEglFSKmsDevice(screenConfig, path)
     , m_gbm_device(nullptr)
@@ -47,7 +46,13 @@ 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;
 }
@@ -56,7 +61,8 @@ 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);
@@ -138,4 +144,10 @@ 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