Support dynamic output enabling/disabling from KScreen

Summary:
We need to keep the DrmOutput object to still have the
WaylandOutputDevice.

Screens currently start off enabled as before.

In order to keep KWin to have a correct index based list of screens we
need to store a second vector of currently enabled outputs for the
screens interface.

Test Plan:
Had dual screens.
Disabled/Enabled each one through the kscreen KCM

Reviewers: #plasma, graesslin

Reviewed By: #plasma, graesslin

Subscribers: ngraham, luebking, broulik, graesslin, plasma-devel, kwin, #kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D8796

plugins/platforms/drm/drm_backend.cpp

@@ -127,7 +127,7 @@ void DrmBackend::outputWentOff()
 void DrmBackend::turnOutputsOn()
 {
     m_dpmsFilter.reset();
-    for (auto it = m_outputs.constBegin(), end = m_outputs.constEnd(); it != end; it++) {
+    for (auto it = m_enabledOutputs.constBegin(), end = m_enabledOutputs.constEnd(); it != end; it++) {
         (*it)->setDpms(DrmOutput::DpmsMode::On);
     }
 }
@@ -138,7 +138,7 @@ void DrmBackend::checkOutputsAreOn()
         // already disabled, all outputs are on
         return;
     }
-    for (auto it = m_outputs.constBegin(), end = m_outputs.constEnd(); it != end; it++) {
+    for (auto it = m_enabledOutputs.constBegin(), end = m_enabledOutputs.constEnd(); it != end; it++) {
         if (!(*it)->isDpmsEnabled()) {
             // dpms still disabled, need to keep the filter
             return;
@@ -396,6 +396,7 @@ void DrmBackend::updateOutputs()
         }
         DrmOutput *removed = *it;
         it = m_outputs.erase(it);
+        m_enabledOutputs.removeOne(removed);
         emit outputRemoved(removed);
         delete removed;
     }
@@ -475,6 +476,7 @@ void DrmBackend::updateOutputs()
     }
     std::sort(connectedOutputs.begin(), connectedOutputs.end(), [] (DrmOutput *a, DrmOutput *b) { return a->m_conn->id() < b->m_conn->id(); });
     m_outputs = connectedOutputs;
+    m_enabledOutputs = connectedOutputs;
     readOutputsConfiguration();
     if (!m_outputs.isEmpty()) {
         emit screensQueried();
@@ -518,18 +520,50 @@ QByteArray DrmBackend::generateOutputConfigurationUuid() const
 void DrmBackend::configurationChangeRequested(KWayland::Server::OutputConfigurationInterface *config)
 {
     const auto changes = config->changes();
-    for (auto it = changes.begin(); it != changes.end(); it++) {
+    bool countChanged = false;
 
+    //process all non-disabling changes
+    for (auto it = changes.begin(); it != changes.end(); it++) {
         KWayland::Server::OutputChangeSet *changeset = it.value();
 
         auto drmoutput = findOutput(it.key()->uuid());
         if (drmoutput == nullptr) {
             qCWarning(KWIN_DRM) << "Could NOT find DrmOutput matching " << it.key()->uuid();
-            return;
+            continue;
+        }
+        if (changeset->enabledChanged() && changeset->enabled() == KWayland::Server::OutputDeviceInterface::Enablement::Enabled) {
+            drmoutput->setEnabled(true);
+            m_enabledOutputs << drmoutput;
+            emit outputAdded(drmoutput);
+            countChanged = true;
         }
         drmoutput->setChanges(changeset);
     }
-    emit screens()->changed();
+    //process any disable requests
+    for (auto it = changes.begin(); it != changes.end(); it++) {
+        KWayland::Server::OutputChangeSet *changeset = it.value();
+        if (changeset->enabledChanged() && changeset->enabled() == KWayland::Server::OutputDeviceInterface::Enablement::Disabled) {
+            if (m_enabledOutputs.count() == 1) {
+                qCWarning(KWIN_DRM) << "Not disabling final screen" << it.key()->uuid();
+                continue;
+            }
+            auto drmoutput = findOutput(it.key()->uuid());
+            if (drmoutput == nullptr) {
+                qCWarning(KWIN_DRM) << "Could NOT find DrmOutput matching " << it.key()->uuid();
+                continue;
+            }
+            drmoutput->setEnabled(false);
+            m_enabledOutputs.removeOne(drmoutput);
+            emit outputRemoved(drmoutput);
+            countChanged = true;
+        }
+    }
+
+    if (countChanged) {
+        emit screensQueried();
+    } else {
+        emit screens()->changed();
+    }
     // KCoreAddons needs kwayland's 2b3f9509ac1 to not crash
     if (KCoreAddons::version() >= QT_VERSION_CHECK(5, 39, 0)) {
         config->setApplied();
@@ -706,11 +740,11 @@ DrmSurfaceBuffer *DrmBackend::createBuffer(const std::shared_ptr<GbmSurface> &su
 
 void DrmBackend::outputDpmsChanged()
 {
-    if (m_outputs.isEmpty()) {
+    if (m_enabledOutputs.isEmpty()) {
         return;
     }
     bool enabled = false;
-    for (auto it = m_outputs.constBegin(); it != m_outputs.constEnd(); ++it) {
+    for (auto it = m_enabledOutputs.constBegin(); it != m_enabledOutputs.constEnd(); ++it) {
         enabled = enabled || (*it)->isDpmsEnabled();
     }
     setOutputsEnabled(enabled);

plugins/platforms/drm/drm_backend.h

@@ -92,6 +92,9 @@ public:
     QVector<DrmOutput*> outputs() const {
         return m_outputs;
     }
+    QVector<DrmOutput*> enabledOutputs() const {
+        return m_enabledOutputs;
+    }
     QVector<DrmPlane*> planes() const {
         return m_planes;
     }
@@ -126,7 +129,13 @@ public Q_SLOTS:
     void turnOutputsOn();
 
 Q_SIGNALS:
+    /**
+     * Emitted whenever an output is removed/disabled
+     */
     void outputRemoved(KWin::DrmOutput *output);
+    /**
+     * Emitted whenever an output is added/enabled
+     */
     void outputAdded(KWin::DrmOutput *output);
 
 protected:
@@ -158,8 +167,11 @@ private:
     QVector<DrmCrtc*> m_crtcs;
     // all connectors
     QVector<DrmConnector*> m_connectors;
-    // currently active output pipelines (planes + crtc + encoder + connector)
+    // active output pipelines (planes + crtc + encoder + connector)
     QVector<DrmOutput*> m_outputs;
+    // active and enabled pipelines (above + wl_output)
+    QVector<DrmOutput*> m_enabledOutputs;
+
     bool m_deleteBufferAfterPageFlip;
     bool m_atomicModeSetting = false;
     bool m_cursorEnabled = false;

plugins/platforms/drm/drm_output.cpp

@@ -183,6 +183,26 @@ qreal DrmOutput::scale() const
     return m_scale;
 }
 
+void DrmOutput::setEnabled(bool enabled)
+{
+    if (enabled == isEnabled()) {
+        return;
+    }
+    if (enabled) {
+        setDpms(DpmsMode::On);
+        initOutput();
+    } else {
+        setDpms(DpmsMode::Off);
+        delete m_waylandOutput.data();
+    }
+    m_waylandOutputDevice->setEnabled(enabled ?
+    KWayland::Server::OutputDeviceInterface::Enablement::Enabled : KWayland::Server::OutputDeviceInterface::Enablement::Disabled);
+}
+
+bool DrmOutput::isEnabled() const
+{
+    return !m_waylandOutput.isNull();
+}
 
 static KWayland::Server::OutputInterface::DpmsMode toWaylandDpmsMode(DrmOutput::DpmsMode mode)
 {
@@ -272,8 +292,6 @@ bool DrmOutput::init(drmModeConnector *connector)
 
     m_internal = connector->connector_type == DRM_MODE_CONNECTOR_LVDS || connector->connector_type == DRM_MODE_CONNECTOR_eDP;
 
-    setDpms(DpmsMode::On);
-
     if (m_internal) {
         connect(kwinApp(), &Application::screensCreated, this,
             [this] {
@@ -297,8 +315,8 @@ bool DrmOutput::init(drmModeConnector *connector)
     m_physicalSize = physicalSize;
 
     initOutputDevice(connector);
-    initOutput();
 
+    setEnabled(true);
     return true;
 }
 
@@ -784,18 +802,13 @@ void DrmOutput::setChanges(KWayland::Server::OutputChangeSet *changes)
 bool DrmOutput::commitChanges()
 {
     Q_ASSERT(!m_waylandOutputDevice.isNull());
-    Q_ASSERT(!m_waylandOutput.isNull());
 
     if (m_changeset.isNull()) {
         qCDebug(KWIN_DRM) << "no changes";
         // No changes to an output is an entirely valid thing
         return true;
     }
-
-    if (m_changeset->enabledChanged()) {
-        qCDebug(KWIN_DRM) << "Setting enabled:";
-        m_waylandOutputDevice->setEnabled(m_changeset->enabled());
-    }
+    //enabledChanged is handled by drmbackend
     if (m_changeset->modeChanged()) {
         qCDebug(KWIN_DRM) << "Setting new mode:" << m_changeset->mode();
         m_waylandOutputDevice->setCurrentMode(m_changeset->mode());

plugins/platforms/drm/drm_output.h

@@ -75,6 +75,15 @@ public:
     bool present(DrmBuffer *buffer);
     void pageFlipped();
 
+    /**
+     * Enable or disable the output.
+     * This differs from setDpms as it also
+     * removes the wl_output
+     * The default is on
+     */
+    void setEnabled(bool enabled);
+    bool isEnabled() const;
+
     /**
      * This sets the changes and tests them against the DRM output
      */

plugins/platforms/drm/screens_drm.cpp

@@ -43,7 +43,7 @@ void DrmScreens::init()
 
 QRect DrmScreens::geometry(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return QRect();
     }
@@ -52,7 +52,7 @@ QRect DrmScreens::geometry(int screen) const
 
 qreal DrmScreens::scale(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return 1;
     }
@@ -61,7 +61,7 @@ qreal DrmScreens::scale(int screen) const
 
 QSize DrmScreens::size(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return QSize();
     }
@@ -70,14 +70,14 @@ QSize DrmScreens::size(int screen) const
 
 void DrmScreens::updateCount()
 {
-    setCount(m_backend->outputs().size());
+    setCount(m_backend->enabledOutputs().size());
 }
 
 int DrmScreens::number(const QPoint &pos) const
 {
     int bestScreen = 0;
     int minDistance = INT_MAX;
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     for (int i = 0; i < outputs.size(); ++i) {
         const QRect &geo = outputs.at(i)->geometry();
         if (geo.contains(pos)) {
@@ -97,7 +97,7 @@ int DrmScreens::number(const QPoint &pos) const
 
 QString DrmScreens::name(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return Screens::name(screen);
     }
@@ -106,7 +106,7 @@ QString DrmScreens::name(int screen) const
 
 float DrmScreens::refreshRate(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return Screens::refreshRate(screen);
     }
@@ -115,7 +115,7 @@ float DrmScreens::refreshRate(int screen) const
 
 QSizeF DrmScreens::physicalSize(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return Screens::physicalSize(screen);
     }
@@ -124,7 +124,7 @@ QSizeF DrmScreens::physicalSize(int screen) const
 
 bool DrmScreens::isInternal(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return false;
     }
@@ -133,7 +133,7 @@ bool DrmScreens::isInternal(int screen) const
 
 bool DrmScreens::supportsTransformations(int screen) const
 {
-    const auto outputs = m_backend->outputs();
+    const auto outputs = m_backend->enabledOutputs();
     if (screen >= outputs.size()) {
         return false;
     }