Disable the GPU process in cases where we can't setup context sharing

This explicitly disables WebGL and automatic Resource transfer through
GL context sharing in cases that we know this won't work.
This is currently the case for the QtQuick 2D Renderer as well as
when using llvmpipe on Windows.

It could be possible to get Chromium to use GL through opengl32sw.dll
but the change would be more intrusive. Fall back to the Chromium
software compositor code path in that case at the cost of losing
WebGL support with llvmpipe.

Change-Id: I9c1d27ed982dccbe005c8742162c343cc6284e74
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>

1 files changed, 45 insertions, 9 deletions

diff --git a/src/core/web_engine_context.cpp b/src/core/web_engine_context.cpp
index d4659f0be..0725e523c 100644
--- a/src/core/web_engine_context.cpp
+++ b/src/core/web_engine_context.cpp
@@ -74,6 +74,7 @@
 #include "type_conversion.h"
 #include "surface_factory_qt.h"
 #include "web_engine_library_info.h"
+#include <QFileInfo>
 #include <QGuiApplication>
 #include <QOpenGLContext>
 #include <QStringList>
@@ -89,6 +90,37 @@ void destroyContext()
     sContext = 0;
 }
 
+bool usingSoftwareDynamicGL()
+{
+#if defined(Q_OS_WIN)
+    HMODULE handle = static_cast<HMODULE>(QOpenGLContext::openGLModuleHandle());
+    wchar_t path[MAX_PATH];
+    DWORD size = GetModuleFileName(handle, path, MAX_PATH);
+    QFileInfo openGLModule(QString::fromWCharArray(path, size));
+    return openGLModule.fileName() == QLatin1String("opengl32sw.dll");
+#else
+    return false;
+#endif
+}
+
+bool usingQtQuick2DRenderer()
+{
+    const QStringList args = QGuiApplication::arguments();
+    QString device;
+    for (int index = 0; index < args.count(); ++index) {
+        if (args.at(index).startsWith(QLatin1String("--device="))) {
+            device = args.at(index).mid(9);
+            break;
+        }
+    }
+
+    if (device.isEmpty())
+        device = QString::fromLocal8Bit(qgetenv("QMLSCENE_DEVICE"));
+
+    // This assumes that the plugin is installed and is going to be used by QtQuick.
+    return device == QLatin1String("softwarecontext");
+}
+
 } // namespace
 
 WebEngineContext::~WebEngineContext()
@@ -181,16 +213,20 @@ WebEngineContext::WebEngineContext()
 
     GLContextHelper::initialize();
 
-    const char *glType;
-    switch (QOpenGLContext::currentContext()->openGLModuleType()) {
-    case QOpenGLContext::LibGL:
-        glType = gfx::kGLImplementationDesktopName;
-        break;
-    case QOpenGLContext::LibGLES:
-        glType = gfx::kGLImplementationEGLName;
-        break;
+    if (usingSoftwareDynamicGL() || usingQtQuick2DRenderer()) {
+        parsedCommandLine->AppendSwitch(switches::kDisableGpu);
+    } else {
+        const char *glType;
+        switch (QOpenGLContext::openGLModuleType()) {
+        case QOpenGLContext::LibGL:
+            glType = gfx::kGLImplementationDesktopName;
+            break;
+        case QOpenGLContext::LibGLES:
+            glType = gfx::kGLImplementationEGLName;
+            break;
+        }
+        parsedCommandLine->AppendSwitchASCII(switches::kUseGL, glType);
     }
-    parsedCommandLine->AppendSwitchASCII(switches::kUseGL, glType);
 
     content::UtilityProcessHostImpl::RegisterUtilityMainThreadFactory(content::CreateInProcessUtilityThread);
     content::RenderProcessHostImpl::RegisterRendererMainThreadFactory(content::CreateInProcessRendererThread);