Windows QPA: Force windows to the main screen in certain AMD GPU setups

A multi-screen setup with an AMD adapter set as the 'main display' leads
to using the AMD drivers for OpenGL. This then causes a crash when calling
SetPixelFormat and similar for windows located on another adapter's
screen. This workaround detects the conditions leading to the crash and moves
the window to the main display.

Task-number: QTBUG-50371
Change-Id: I4007c490bdcdc13d6e8bce82983b150aa4930338
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 83 insertions, 1 deletions

diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 528927b0fb..9c31409644 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -58,6 +58,7 @@
 #else
 #  include "qwindowsopenglcontext.h"
 #endif
+#include "qwindowsopengltester.h"
 #ifdef QT_NO_CURSOR
 #  include "qwindowscursor.h"
 #endif
@@ -541,6 +542,84 @@ static inline void fixTopLevelWindowFlags(Qt::WindowFlags &flags)
         flags |= Qt::FramelessWindowHint;
 }
 
+static QScreen *screenForName(const QWindow *w, const QString &name)
+{
+    QScreen *winScreen = w ? w->screen() : QGuiApplication::primaryScreen();
+    if (winScreen && winScreen->name() != name) {
+        const auto screens = winScreen->virtualSiblings();
+        for (QScreen *screen : screens) {
+            if (screen->name() == name)
+                return screen;
+        }
+    }
+    return winScreen;
+}
+
+static QScreen *forcedScreenForGLWindow(const QWindow *w)
+{
+    const QString forceToScreen = GpuDescription::detect().gpuSuitableScreen;
+    return forceToScreen.isEmpty() ? nullptr : screenForName(w, forceToScreen);
+}
+
+static QPoint calcPosition(const QWindow *w, const QWindowCreationContextPtr &context, const QMargins &invMargins)
+{
+    const QPoint orgPos(context->frameX - invMargins.left(), context->frameY - invMargins.top());
+
+    if (!w || (!w->isTopLevel() && w->surfaceType() != QWindow::OpenGLSurface))
+        return orgPos;
+
+    // Workaround for QTBUG-50371
+    const QScreen *screenForGL = forcedScreenForGLWindow(w);
+    if (!screenForGL)
+        return orgPos;
+
+    const QPoint posFrame(context->frameX, context->frameY);
+    const QMargins margins = context->margins;
+    const QRect scrGeo = screenForGL->handle()->availableGeometry();
+
+    // Point is already in the required screen.
+    if (scrGeo.contains(orgPos))
+        return orgPos;
+
+    // If the visible part of the window is already in the
+    // required screen, just ignore the invisible offset.
+    if (scrGeo.contains(posFrame))
+        return posFrame;
+
+    // Find the original screen containing the coordinates.
+    const QList<QScreen *> screens = screenForGL->virtualSiblings();
+    const QScreen *orgScreen = nullptr;
+    for (QScreen *screen : screens) {
+        if (screen->handle()->availableGeometry().contains(posFrame)) {
+            orgScreen = screen;
+            break;
+        }
+    }
+    const QPoint ctPos = QPoint(qMax(scrGeo.left(), scrGeo.center().x()
+                                     + (margins.right() - margins.left() - context->frameWidth)/2),
+                                qMax(scrGeo.top(), scrGeo.center().y()
+                                     + (margins.bottom() - margins.top() - context->frameHeight)/2));
+
+    // If initial coordinates were outside all screens, center the window on the required screen.
+    if (!orgScreen)
+        return ctPos;
+
+    const QRect orgGeo = orgScreen->handle()->availableGeometry();
+    const QRect orgFrame(QPoint(context->frameX, context->frameY),
+                         QSize(context->frameWidth, context->frameHeight));
+
+    // Window would be centered on orgScreen. Center it on the required screen.
+    if (orgGeo.center() == (orgFrame - margins).center())
+        return ctPos;
+
+    // Transform the coordinates to map them into the required screen.
+    const QPoint newPos(scrGeo.left() + ((posFrame.x() - orgGeo.left()) * scrGeo.width()) / orgGeo.width(),
+                        scrGeo.top() + ((posFrame.y() - orgGeo.top()) * scrGeo.height()) / orgGeo.height());
+    const QPoint newPosNoMargin(newPos.x() - invMargins.left(), newPos.y() - invMargins.top());
+
+    return scrGeo.contains(newPosNoMargin) ? newPosNoMargin : newPos;
+}
+
 void WindowCreationData::fromWindow(const QWindow *w, const Qt::WindowFlags flagsIn,
                                     unsigned creationFlags)
 {
@@ -688,9 +767,12 @@ QWindowsWindowData
         << " custom margins: " << context->customMargins
         << " invisible margins: " << invMargins;
 
+
+    QPoint pos = calcPosition(w, context, invMargins);
+
     result.hwnd = CreateWindowEx(exStyle, classNameUtf16, titleUtf16,
                                  style,
-                                 context->frameX - invMargins.left(), context->frameY - invMargins.top(),
+                                 pos.x(), pos.y(),
                                  context->frameWidth, context->frameHeight,
                                  parentHandle, NULL, appinst, NULL);
     qCDebug(lcQpaWindows).nospace()