Merge lp:~gerboland/qtubuntu/surface-visible-hidden-side-channel into lp:qtubuntu

[kevin gunn]

Lifecycle events emit expose events to safely stop & resume the renderer threads.

We don't use hide/show directly as hide causes Qt to stop the renderer, but then release the GL context and its resources. Expose events just stop & resume the renderer without altering the context.

The Qt5.2 blocking at eglSwapBuffers fix is to never block, but to stop clients rendering continually, we use a side-channel to notify clients that their surfaces are hidden and they can stop rendering, and when they can resume.

 * Is your branch in sync with latest trunk (e.g. bzr pull lp:trunk -> no changes)
Y
 * Did you build your software in a clean sbuild/pbuilder chroot or ppa?
Y
 * Did you build your software in a clean sbuild/pbuilder armhf chroot or ppa?
Y
 * Has a 5 minute exploratory testing run been executed on N4?
Y
 * If you changed the packaging (debian), did you subscribe a core-dev to this MP?
N/A
 * What components might get impacted by your changes?
Any app that renders
 * Have you requested review by the teams of these owning components?
No, this is very low level component shared with all Qt apps on touch, so if one is broken, all would be.

[Gerry Boland (gerboland)]

To test, fetch this file and save on the device:
http://people.canonical.com/~gerboland/dateTime.qml
Run it with this command (with shell unlocked):

QSG_RENDER_TIMING=1 qmlscene dateTime.qml
--desktop_file_hint=/usr/share/applications/address-book-app.desktop

You should see the time printed on screen, and being printed on your
console once per second. You'll also see rendering statistics once per frame.

Now hit your power key. You should see that the render statistics stop,
yet you still get the time printed on your console. (note lifecycle
doesn't apply to manually started apps).

Hit the power key again, and unlock the greeter. Rendering should resume
immediately.

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:220
http://jenkins.qa.ubuntu.com/job/qtubuntu-ci/133/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/qtubuntu-trusty-armhf-ci/44
        deb: http://jenkins.qa.ubuntu.com/job/qtubuntu-trusty-armhf-ci/44/artifact/work/output/*zip*/output.zip

Click here to trigger a rebuild:
http://s-jenkins.ubuntu-ci:8080/job/qtubuntu-ci/133/rebuild

review: Approve (continuous-integration)

[lp:~gerboland/qtubuntu/surface-visible-hidden-side-channel]

221. By Gerry Boland on 2014-04-16

Using the hide/show events at all is dangerous, rely solely on expose

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:221
http://jenkins.qa.ubuntu.com/job/qtubuntu-ci/134/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/qtubuntu-trusty-armhf-ci/45
        deb: http://jenkins.qa.ubuntu.com/job/qtubuntu-trusty-armhf-ci/45/artifact/work/output/*zip*/output.zip

Click here to trigger a rebuild:
http://s-jenkins.ubuntu-ci:8080/job/qtubuntu-ci/134/rebuild

review: Approve (continuous-integration)

=== modified file 'src/platforms/ubuntu/ubuntucommon/integration.cc'
--- src/platforms/ubuntu/ubuntucommon/integration.cc	2013-10-14 09:55:36 +0000
+++ src/platforms/ubuntu/ubuntucommon/integration.cc	2014-04-16 16:30:46 +0000
@@ -19,7 +19,7 @@
 #include "clipboard.h"
 #include "input_adaptor_factory.h"
 #include "base/logging.h"
-#include <QtCore/QCoreApplication>
+#include <QGuiApplication>
 #include <qpa/qplatformnativeinterface.h>
 #include <qpa/qplatforminputcontextfactory_p.h>
 #include <qpa/qplatforminputcontext.h>
@@ -35,6 +35,10 @@
   QUbuntuIntegration* integration = static_cast<QUbuntuIntegration*>(context);
   integration->screen()->toggleSensors(true);
   QCoreApplication::postEvent(QCoreApplication::instance(), new QEvent(QEvent::ApplicationActivate));
+
+  Q_FOREACH(QWindow *window, QGuiApplication::allWindows()) {
+    QGuiApplication::postEvent(window, new QExposeEvent( window->geometry() ));
+  }
 }
 
 static void aboutToStopCallback(UApplicationArchive *archive, void* context) {
@@ -43,6 +47,11 @@
   QUbuntuIntegration* integration = static_cast<QUbuntuIntegration*>(context);
   integration->screen()->toggleSensors(false);
   integration->inputContext()->hideInputPanel();
+
+  Q_FOREACH(QWindow *window, QGuiApplication::allWindows()) {
+    QGuiApplication::postEvent(window, new QExposeEvent( QRegion() ));
+  }
+
   QCoreApplication::postEvent(QCoreApplication::instance(), new QEvent(QEvent::ApplicationDeactivate));
 }
 

=== modified file 'src/platforms/ubuntu/ubuntucommon/window.cc'
--- src/platforms/ubuntu/ubuntucommon/window.cc	2013-12-11 04:32:09 +0000
+++ src/platforms/ubuntu/ubuntucommon/window.cc	2014-04-16 16:30:46 +0000
@@ -24,6 +24,7 @@
 #include "base/logging.h"
 #include <qpa/qwindowsysteminterface.h>
 #include <ubuntu/application/ui/window.h>
+#include <QRegion>
 
 static void eventCallback(void* context, const Event* event) {
   DLOG("eventCallback (context=%p, event=%p)", context, event);
@@ -41,7 +42,9 @@
     , systemSession_(systemSession)
     , uainstance_(instance)
     , screen_(screen)
-    , isShell_(isShell) {
+    , isShell_(isShell)
+    , exposed_(false)
+{
   if (!systemSession) {
     // Non-system sessions can't resize the window geometry.
     geometry_ = screen->availableGeometry();
@@ -183,12 +186,45 @@
 void QUbuntuWindow::setVisible(bool visible) {
   DLOG("QUbuntuWindow::setVisible (this=%p, visible=%s)", this, visible ? "true" : "false");
   if (isShell_ == false)
-      screen_->toggleSensors(visible);
+    screen_->toggleSensors(visible);
+
+  setExposed(visible);
 
   if (visible) {
     ua_ui_window_show(window_);
+  } else {
+    ua_ui_window_hide(window_);
+  }
+}
+
+bool QUbuntuWindow::isExposed() const {
+  return exposed_;
+}
+
+void QUbuntuWindow::setExposed(const bool exposed) {
+  DLOG("QUbuntuWindow::setExposed (this=%p, exposed=%s)", this, exposed ? "true" : "false");
+
+  if (exposed_ == exposed)
+    return;
+
+  exposed_ = exposed;
+  if (exposed_) {
+    QWindowSystemInterface::handleExposeEvent(window(), geometry());
+  } else {
     QWindowSystemInterface::handleExposeEvent(window(), QRect());
-  } else {
-    ua_ui_window_hide(window_);
+  }
+}
+
+void QUbuntuWindow::windowEvent(QEvent *event) {
+  if (event->type() == QEvent::Expose) {
+    QRegion region = static_cast<QExposeEvent *>(event)->region();
+
+    if (region.isEmpty()) {
+      // hiding window causes Qt to release the GL context and its resources, which is a bit severe
+      // Instead can use the exposure system to stop the rendering loop, but hold onto the resources
+      setExposed(false);
+    } else {
+      setExposed(true);
+    }
   }
 }

=== modified file 'src/platforms/ubuntu/ubuntucommon/window.h'
--- src/platforms/ubuntu/ubuntucommon/window.h	2013-08-02 21:32:00 +0000
+++ src/platforms/ubuntu/ubuntucommon/window.h	2014-04-16 16:30:46 +0000
@@ -34,12 +34,15 @@
   void setGeometry(const QRect&);
   void setWindowState(Qt::WindowState state);
   void setVisible(bool visible);
+  bool isExposed() const;
+  void windowEvent(QEvent *event);
 
   QUbuntuInput* input_;
 
  private:
   void createWindow();
   void moveResize(const QRect& rect);
+  void setExposed(const bool exposed);
 
   UAUiWindow* window_;
   Qt::WindowState state_;
@@ -49,6 +52,7 @@
   UAUiWindowProperties* wprops_;
   QUbuntuScreen* screen_;
   bool isShell_;
+  bool exposed_;
 };
 
 #endif  // QUBUNTUWINDOW_H