eglfs: Configurable screen order in the virtual desktop

Say one wants a virtual desktop with the display on HDMI above
the display on DisplayPort:

{
  "device": "drm-nvdc",
  "virtualDesktopOrientation": "vertical",
  "outputs": [
    {
      "name": "HDMI1",
      "virtualIndex": 0
    },
    {
      "name": "DP1"
    }
  ]
}

Undefined virtualIndex values map to INT_MAX and will go after the
explicitly specified ones. However, the sorting is stable so the original
order from the DRM connector list is preserved between such outputs.

Task-number: QTBUG-55188
Change-Id: I204fb08205ea7dbfbcdefd1d22ed22f5387f3e8c
Reviewed-by: Andy Nichols <andy.nichols@qt.io>

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.cpp

@@ -142,10 +142,10 @@ void QEglFSKmsGbmDevice::handleDrmEvent()
     drmHandleEvent(fd(), &drmEvent);
 }
 
-QEglFSKmsScreen *QEglFSKmsGbmDevice::createScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output, QPoint position)
+QEglFSKmsScreen *QEglFSKmsGbmDevice::createScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output)
 {
     static bool firstScreen = true;
-    QEglFSKmsGbmScreen *screen = new QEglFSKmsGbmScreen(integration, device, output, position);
+    QEglFSKmsGbmScreen *screen = new QEglFSKmsGbmScreen(integration, device, output);
 
     if (firstScreen && integration->hwCursor()) {
         m_globalCursor = new QEglFSKmsGbmCursor(screen);

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmdevice.h

@@ -68,8 +68,7 @@ public:
 
     virtual QEglFSKmsScreen *createScreen(QEglFSKmsIntegration *integration,
                                           QEglFSKmsDevice *device,
-                                          QEglFSKmsOutput output,
+                                          QEglFSKmsOutput output) Q_DECL_OVERRIDE;
-                                          QPoint position) Q_DECL_OVERRIDE;
 
 private:
     Q_DISABLE_COPY(QEglFSKmsGbmDevice)

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.cpp

@@ -93,10 +93,9 @@ QEglFSKmsGbmScreen::FrameBuffer *QEglFSKmsGbmScreen::framebufferForBufferObject(
 }
 
 QEglFSKmsGbmScreen::QEglFSKmsGbmScreen(QEglFSKmsIntegration *integration,
-                                 QEglFSKmsDevice *device,
+                                       QEglFSKmsDevice *device,
-                                 QEglFSKmsOutput output,
+                                       QEglFSKmsOutput output)
-                                 QPoint position)
+    : QEglFSKmsScreen(integration, device, output)
-    : QEglFSKmsScreen(integration, device, output, position)
     , m_gbm_surface(Q_NULLPTR)
     , m_gbm_bo_current(Q_NULLPTR)
     , m_gbm_bo_next(Q_NULLPTR)

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms/qeglfskmsgbmscreen.h

@@ -55,9 +55,8 @@ class QEglFSKmsGbmScreen : public QEglFSKmsScreen
 {
 public:
     QEglFSKmsGbmScreen(QEglFSKmsIntegration *integration,
-                    QEglFSKmsDevice *device,
+                       QEglFSKmsDevice *device,
-                    QEglFSKmsOutput output,
+                       QEglFSKmsOutput output);
-                    QPoint position);
     ~QEglFSKmsGbmScreen();
 
     QPlatformCursor *cursor() const Q_DECL_OVERRIDE;

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldevice.cpp

@@ -83,9 +83,9 @@ EGLNativeDisplayType QEglFSKmsEglDevice::nativeDisplay() const
 }
 
 QEglFSKmsScreen *QEglFSKmsEglDevice::createScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device,
-                                                  QEglFSKmsOutput output, QPoint position)
+                                                  QEglFSKmsOutput output)
 {
-    QEglFSKmsScreen *screen = new QEglFSKmsEglDeviceScreen(integration, device, output, position);
+    QEglFSKmsScreen *screen = new QEglFSKmsEglDeviceScreen(integration, device, output);
 
     if (!m_globalCursor && !integration->separateScreens()) {
         qCDebug(qLcEglfsKmsDebug, "Creating new global mouse cursor");

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldevice.h

@@ -58,8 +58,7 @@ public:
 
     virtual QEglFSKmsScreen *createScreen(QEglFSKmsIntegration *integration,
                                           QEglFSKmsDevice *device,
-                                          QEglFSKmsOutput output,
+                                          QEglFSKmsOutput output) Q_DECL_OVERRIDE;
-                                          QPoint position) Q_DECL_OVERRIDE;
 
     QPlatformCursor *globalCursor() { return m_globalCursor; }
     void destroyGlobalCursor();

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldevicescreen.cpp

@@ -43,8 +43,8 @@
 
 QT_BEGIN_NAMESPACE
 
-QEglFSKmsEglDeviceScreen::QEglFSKmsEglDeviceScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output, QPoint position)
+QEglFSKmsEglDeviceScreen::QEglFSKmsEglDeviceScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output)
-    : QEglFSKmsScreen(integration, device, output, position)
+    : QEglFSKmsScreen(integration, device, output)
 {
 }
 

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_egldevice/qeglfskmsegldevicescreen.h

@@ -49,8 +49,7 @@ class QEglFSKmsEglDeviceScreen : public QEglFSKmsScreen
 public:
     QEglFSKmsEglDeviceScreen(QEglFSKmsIntegration *integration,
                              QEglFSKmsDevice *device,
-                             QEglFSKmsOutput output,
+                             QEglFSKmsOutput output);
-                             QPoint position);
     ~QEglFSKmsEglDeviceScreen();
 
     QPlatformCursor *cursor() const Q_DECL_OVERRIDE;

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_support/qeglfskmsdevice.cpp

@@ -159,7 +159,7 @@ static bool parseModeline(const QByteArray &text, drmModeModeInfoPtr mode)
     return true;
 }
 
-QEglFSKmsScreen *QEglFSKmsDevice::createScreenForConnector(drmModeResPtr resources, drmModeConnectorPtr connector, QPoint pos)
+QEglFSKmsScreen *QEglFSKmsDevice::createScreenForConnector(drmModeResPtr resources, drmModeConnectorPtr connector, int *virtualIndex)
 {
     const QByteArray connectorName = nameForConnector(connector);
 
@@ -192,6 +192,8 @@ QEglFSKmsScreen *QEglFSKmsDevice::createScreenForConnector(drmModeResPtr resourc
         qWarning("Invalid mode \"%s\" for output %s", mode.constData(), connectorName.constData());
         configuration = OutputConfigPreferred;
     }
+    if (virtualIndex)
+        *virtualIndex = userConnectorConfig.value(QStringLiteral("virtualIndex"), INT_MAX).toInt();
 
     const uint32_t crtc_id = resources->crtcs[crtc];
 
@@ -303,6 +305,7 @@ QEglFSKmsScreen *QEglFSKmsDevice::createScreenForConnector(drmModeResPtr resourc
             physSize.setHeight(connector->mmHeight);
         }
     }
+    qCDebug(qLcEglfsKmsDebug) << "Physical size is" << physSize << "mm" << "for output" << connectorName;
 
     QEglFSKmsOutput output = {
         QString::fromUtf8(connectorName),
@@ -320,7 +323,7 @@ QEglFSKmsScreen *QEglFSKmsDevice::createScreenForConnector(drmModeResPtr resourc
     m_crtc_allocator |= (1 << output.crtc_id);
     m_connector_allocator |= (1 << output.connector_id);
 
-    return createScreen(m_integration, this, output, pos);
+    return createScreen(m_integration, this, output);
 }
 
 drmModePropertyPtr QEglFSKmsDevice::connectorProperty(drmModeConnectorPtr connector, const QByteArray &name)
@@ -352,6 +355,26 @@ QEglFSKmsDevice::~QEglFSKmsDevice()
 {
 }
 
+struct OrderedScreen
+{
+    OrderedScreen() : screen(nullptr), index(-1) { }
+    OrderedScreen(QEglFSKmsScreen *screen, int index) : screen(screen), index(index) { }
+    QEglFSKmsScreen *screen;
+    int index;
+};
+
+QDebug operator<<(QDebug dbg, const OrderedScreen &s)
+{
+    QDebugStateSaver saver(dbg);
+    dbg.nospace() << "OrderedScreen(" << s.screen << " : " << s.index << ")";
+    return dbg;
+}
+
+static bool orderedScreenLessThan(const OrderedScreen &a, const OrderedScreen &b)
+{
+    return a.index < b.index;
+}
+
 void QEglFSKmsDevice::createScreens()
 {
     drmModeResPtr resources = drmModeGetResources(m_dri_fd);
@@ -360,38 +383,46 @@ void QEglFSKmsDevice::createScreens()
         return;
     }
 
-    QEglFSKmsScreen *primaryScreen = Q_NULLPTR;
+    QVector<OrderedScreen> screens;
-    QList<QPlatformScreen *> siblings;
-    QPoint pos(0, 0);
-    QEglFSIntegration *integration = static_cast<QEglFSIntegration *>(QGuiApplicationPrivate::platformIntegration());
 
     for (int i = 0; i < resources->count_connectors; i++) {
         drmModeConnectorPtr connector = drmModeGetConnector(m_dri_fd, resources->connectors[i]);
         if (!connector)
             continue;
 
-        QEglFSKmsScreen *screen = createScreenForConnector(resources, connector, pos);
+        int virtualIndex;
-        if (screen) {
+        QEglFSKmsScreen *screen = createScreenForConnector(resources, connector, &virtualIndex);
-            integration->addScreen(screen);
+        if (screen)
-
+            screens.append(OrderedScreen(screen, virtualIndex));
-            if (m_integration->virtualDesktopLayout() == QEglFSKmsIntegration::VirtualDesktopLayoutVertical)
-                pos.ry() += screen->geometry().height();
-            else
-                pos.rx() += screen->geometry().width();
-
-            siblings << screen;
-
-            if (!primaryScreen)
-                primaryScreen = screen;
-        }
 
         drmModeFreeConnector(connector);
     }
 
     drmModeFreeResources(resources);
 
+    // Use stable sort to preserve the original order for outputs with unspecified indices.
+    std::stable_sort(screens.begin(), screens.end(), orderedScreenLessThan);
+    qCDebug(qLcEglfsKmsDebug) << "Sorted screen list:" << screens;
+
+    QPoint pos(0, 0);
+    QList<QPlatformScreen *> siblings;
+    QEglFSIntegration *qpaIntegration = static_cast<QEglFSIntegration *>(QGuiApplicationPrivate::platformIntegration());
+
+    for (const OrderedScreen &orderedScreen : screens) {
+        QEglFSKmsScreen *s = orderedScreen.screen;
+        // set up a horizontal or vertical virtual desktop
+        s->setVirtualPosition(pos);
+        if (m_integration->virtualDesktopLayout() == QEglFSKmsIntegration::VirtualDesktopLayoutVertical)
+            pos.ry() += s->geometry().height();
+        else
+            pos.rx() += s->geometry().width();
+        qCDebug(qLcEglfsKmsDebug) << "Adding screen" << s << "to QPA with geometry" << s->geometry();
+        qpaIntegration->addScreen(s);
+        siblings << s;
+    }
+
     if (!m_integration->separateScreens()) {
-        // set up a virtual desktop
+        // enable the virtual desktop
         Q_FOREACH (QPlatformScreen *screen, siblings)
             static_cast<QEglFSKmsScreen *>(screen)->setVirtualSiblings(siblings);
     }
@@ -407,9 +438,9 @@ QString QEglFSKmsDevice::devicePath() const
     return m_path;
 }
 
-QEglFSKmsScreen *QEglFSKmsDevice::createScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output, QPoint position)
+QEglFSKmsScreen *QEglFSKmsDevice::createScreen(QEglFSKmsIntegration *integration, QEglFSKmsDevice *device, QEglFSKmsOutput output)
 {
-    return new QEglFSKmsScreen(integration, device, output, position);
+    return new QEglFSKmsScreen(integration, device, output);
 }
 
 void QEglFSKmsDevice::setFd(int fd)

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_support/qeglfskmsdevice.h

@@ -68,8 +68,7 @@ public:
 protected:
     virtual QEglFSKmsScreen *createScreen(QEglFSKmsIntegration *integration,
                                           QEglFSKmsDevice *device,
-                                          QEglFSKmsOutput output,
+                                          QEglFSKmsOutput output);
-                                          QPoint position);
     void setFd(int fd);
 
     QEglFSKmsIntegration *m_integration;
@@ -80,7 +79,7 @@ protected:
     quint32 m_connector_allocator;
 
     int crtcForConnector(drmModeResPtr resources, drmModeConnectorPtr connector);
-    QEglFSKmsScreen *createScreenForConnector(drmModeResPtr resources, drmModeConnectorPtr connector, QPoint pos);
+    QEglFSKmsScreen *createScreenForConnector(drmModeResPtr resources, drmModeConnectorPtr connector, int *virtualIndex);
     drmModePropertyPtr connectorProperty(drmModeConnectorPtr connector, const QByteArray &name);
 
     static void pageFlipHandler(int fd,

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_support/qeglfskmsintegration.cpp

@@ -201,7 +201,7 @@ void QEglFSKmsIntegration::loadConfig()
         else if (vdOriString == QLatin1String("vertical"))
             m_virtualDesktopLayout = VirtualDesktopLayoutVertical;
         else
-            qCWarning(qLcEglfsKmsDebug) << "Unknown virtualDesktop value" << vdOriString;
+            qCWarning(qLcEglfsKmsDebug) << "Unknown virtualDesktopOrientation value" << vdOriString;
     }
 
     const QJsonArray outputs = object.value(QLatin1String("outputs")).toArray();

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_support/qeglfskmsscreen.cpp

@@ -71,13 +71,11 @@ private:
 
 QEglFSKmsScreen::QEglFSKmsScreen(QEglFSKmsIntegration *integration,
                                  QEglFSKmsDevice *device,
-                                 QEglFSKmsOutput output,
+                                 QEglFSKmsOutput output)
-                                 QPoint position)
     : QEglFSScreen(eglGetDisplay(device->nativeDisplay()))
     , m_integration(integration)
     , m_device(device)
     , m_output(output)
-    , m_pos(position)
     , m_powerState(PowerStateOn)
     , m_interruptHandler(new QEglFSKmsInterruptHandler(this))
 {
@@ -98,34 +96,19 @@ QEglFSKmsScreen::~QEglFSKmsScreen()
     delete m_interruptHandler;
 }
 
+void QEglFSKmsScreen::setVirtualPosition(const QPoint &pos)
+{
+    m_pos = pos;
+}
+
 // Reimplement rawGeometry(), not geometry(). The base class implementation of
 // geometry() calls rawGeometry() and may apply additional transforms.
 QRect QEglFSKmsScreen::rawGeometry() const
 {
     const int mode = m_output.mode;
-    QRect r(m_pos.x(), m_pos.y(),
+    return QRect(m_pos.x(), m_pos.y(),
-            m_output.modes[mode].hdisplay,
+                 m_output.modes[mode].hdisplay,
-            m_output.modes[mode].vdisplay);
+                 m_output.modes[mode].vdisplay);
-
-    static int rotation = qEnvironmentVariableIntValue("QT_QPA_EGLFS_ROTATION");
-    switch (rotation) {
-    case 0:
-    case 180:
-    case -180:
-        break;
-    case 90:
-    case -90: {
-        int h = r.height();
-        r.setHeight(r.width());
-        r.setWidth(h);
-        break;
-    }
-    default:
-        qWarning("Invalid rotation %d specified in QT_QPA_EGLFS_ROTATION", rotation);
-        break;
-    }
-
-    return r;
 }
 
 int QEglFSKmsScreen::depth() const

src/plugins/platforms/eglfs/deviceintegration/eglfs_kms_support/qeglfskmsscreen.h

@@ -74,11 +74,13 @@ class Q_EGLFS_EXPORT QEglFSKmsScreen : public QEglFSScreen
 public:
     QEglFSKmsScreen(QEglFSKmsIntegration *integration,
                     QEglFSKmsDevice *device,
-                    QEglFSKmsOutput output,
+                    QEglFSKmsOutput output);
-                    QPoint position);
     ~QEglFSKmsScreen();
 
+    void setVirtualPosition(const QPoint &pos);
+
     QRect rawGeometry() const Q_DECL_OVERRIDE;
+
     int depth() const Q_DECL_OVERRIDE;
     QImage::Format format() const Q_DECL_OVERRIDE;