From 13fd3e9611391742b4bea86cb2f4740534daf695 Mon Sep 17 00:00:00 2001
From: Oliver Wolff <oliver.wolff@theqtcompany.com>
Date: Wed, 2 Dec 2015 13:17:30 +0100
Subject: winrt: Fix application hang on sensor start/stop

If addition and removal are not done in the Xaml thread, the functions
might not return at all.

Task-number: QTBUG-49741
Change-Id: Iabdea2c7ee18bf851ab70adfeb28b09781b8b609
Reviewed-by: Andrew Knight <andrew.knight@intopalo.com>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@theqtcompany.com>
---
 src/plugins/sensors/winrt/winrt.pro                |  2 +-
 src/plugins/sensors/winrt/winrtaccelerometer.cpp   | 42 ++++++++++++--------
 .../sensors/winrt/winrtambientlightsensor.cpp      | 42 ++++++++++++--------
 src/plugins/sensors/winrt/winrtcompass.cpp         | 45 +++++++++++++---------
 src/plugins/sensors/winrt/winrtgyroscope.cpp       | 42 ++++++++++++--------
 .../sensors/winrt/winrtorientationsensor.cpp       | 42 ++++++++++++--------
 src/plugins/sensors/winrt/winrtrotationsensor.cpp  | 42 ++++++++++++--------
 7 files changed, 156 insertions(+), 101 deletions(-)

diff --git a/src/plugins/sensors/winrt/winrt.pro b/src/plugins/sensors/winrt/winrt.pro
index 4a03bf2e..67ae5304 100644
--- a/src/plugins/sensors/winrt/winrt.pro
+++ b/src/plugins/sensors/winrt/winrt.pro
@@ -1,5 +1,5 @@
 TARGET = qtsensors_winrt
-QT = sensors core
+QT = sensors core core_private
 
 PLUGIN_TYPE = sensors
 PLUGIN_CLASS_NAME = WinRtSensorPlugin
diff --git a/src/plugins/sensors/winrt/winrtaccelerometer.cpp b/src/plugins/sensors/winrt/winrtaccelerometer.cpp
index f2728a86..fba9594c 100644
--- a/src/plugins/sensors/winrt/winrtaccelerometer.cpp
+++ b/src/plugins/sensors/winrt/winrtaccelerometer.cpp
@@ -38,7 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QAccelerometerReading>
+#include <private/qeventdispatcher_winrt_p.h>
 
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -114,20 +116,24 @@ WinRtAccelerometer::WinRtAccelerometer(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtAccelerometerPrivate(this))
 {
     Q_D(WinRtAccelerometer);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Accelerometer);
-    ComPtr<IAccelerometerStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize accelerometer factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Accelerometer);
+        ComPtr<IAccelerometerStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize accelerometer factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default accelerometer."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default accelerometer."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -158,9 +164,11 @@ void WinRtAccelerometer::start()
     if (d->token.value)
         return;
 
-    ComPtr<AccelerometerReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<AccelerometerReadingHandler> callback =
             Callback<AccelerometerReadingHandler>(d, &WinRtAccelerometerPrivate::readingChanged);
-    HRESULT hr = d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+        return d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -189,14 +197,16 @@ void WinRtAccelerometer::stop()
     if (!d->token.value)
         return;
 
-    HRESULT hr = d->sensor->remove_ReadingChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_ReadingChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
         sensorError(hr);
         return;
     }
-    d->sensor->put_ReportInterval(0);
+    hr = d->sensor->put_ReportInterval(0);
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to reset report interval."
                                   << qt_error_string(hr);
diff --git a/src/plugins/sensors/winrt/winrtambientlightsensor.cpp b/src/plugins/sensors/winrt/winrtambientlightsensor.cpp
index b1e1c52c..d0d7fd7d 100644
--- a/src/plugins/sensors/winrt/winrtambientlightsensor.cpp
+++ b/src/plugins/sensors/winrt/winrtambientlightsensor.cpp
@@ -38,7 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QAmbientLightSensor>
+#include <private/qeventdispatcher_winrt_p.h>
 
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -113,20 +115,24 @@ WinRtAmbientLightSensor::WinRtAmbientLightSensor(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtAmbientLightSensorPrivate(this))
 {
     Q_D(WinRtAmbientLightSensor);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_LightSensor);
-    ComPtr<ILightSensorStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize light sensor factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_LightSensor);
+        ComPtr<ILightSensorStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize light sensor factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default light sensor."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default light sensor."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -157,9 +163,11 @@ void WinRtAmbientLightSensor::start()
     if (d->token.value)
         return;
 
-    ComPtr<LightSensorReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<LightSensorReadingHandler> callback =
             Callback<LightSensorReadingHandler>(d, &WinRtAmbientLightSensorPrivate::readingChanged);
-    HRESULT hr = d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+        return d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -188,14 +196,16 @@ void WinRtAmbientLightSensor::stop()
     if (!d->token.value)
         return;
 
-    HRESULT hr = d->sensor->remove_ReadingChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_ReadingChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
         sensorError(hr);
         return;
     }
-    d->sensor->put_ReportInterval(0);
+    hr = d->sensor->put_ReportInterval(0);
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to reset report interval."
                                   << qt_error_string(hr);
diff --git a/src/plugins/sensors/winrt/winrtcompass.cpp b/src/plugins/sensors/winrt/winrtcompass.cpp
index 9c57db9d..22f4ac5b 100644
--- a/src/plugins/sensors/winrt/winrtcompass.cpp
+++ b/src/plugins/sensors/winrt/winrtcompass.cpp
@@ -38,9 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QCompass>
+#include <private/qeventdispatcher_winrt_p.h>
 
-QT_USE_NAMESPACE
-
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -133,20 +133,24 @@ WinRtCompass::WinRtCompass(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtCompassPrivate(this))
 {
     Q_D(WinRtCompass);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Compass);
-    ComPtr<ICompassStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize light sensor factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Compass);
+        ComPtr<ICompassStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize light sensor factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default compass."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default compass."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -177,9 +181,11 @@ void WinRtCompass::start()
     if (d->token.value)
         return;
 
-    ComPtr<CompassReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<CompassReadingHandler> callback =
             Callback<CompassReadingHandler>(d, &WinRtCompassPrivate::readingChanged);
-    HRESULT hr = d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+        return d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -207,15 +213,16 @@ void WinRtCompass::stop()
         return;
     if (!d->token.value)
         return;
-
-    HRESULT hr = d->sensor->remove_ReadingChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_ReadingChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
         sensorError(hr);
         return;
     }
-    d->sensor->put_ReportInterval(0);
+    hr = d->sensor->put_ReportInterval(0);
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to reset report interval."
                                   << qt_error_string(hr);
diff --git a/src/plugins/sensors/winrt/winrtgyroscope.cpp b/src/plugins/sensors/winrt/winrtgyroscope.cpp
index e7910ab2..70d7980f 100644
--- a/src/plugins/sensors/winrt/winrtgyroscope.cpp
+++ b/src/plugins/sensors/winrt/winrtgyroscope.cpp
@@ -38,7 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QGyroscope>
+#include <private/qeventdispatcher_winrt_p.h>
 
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -111,20 +113,24 @@ WinRtGyroscope::WinRtGyroscope(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtGyroscopePrivate(this))
 {
     Q_D(WinRtGyroscope);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Gyrometer);
-    ComPtr<IGyrometerStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize gyroscope sensor factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Gyrometer);
+        ComPtr<IGyrometerStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize gyroscope sensor factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default gyroscope sensor."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default gyroscope sensor."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -155,9 +161,11 @@ void WinRtGyroscope::start()
     if (d->token.value)
         return;
 
-    ComPtr<InclinometerReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<InclinometerReadingHandler> callback =
             Callback<InclinometerReadingHandler>(d, &WinRtGyroscopePrivate::readingChanged);
-    HRESULT hr = d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+        return d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -186,14 +194,16 @@ void WinRtGyroscope::stop()
     if (!d->token.value)
         return;
 
-    HRESULT hr = d->sensor->remove_ReadingChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_ReadingChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
         sensorError(hr);
         return;
     }
-    d->sensor->put_ReportInterval(0);
+    hr = d->sensor->put_ReportInterval(0);
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to reset report interval."
                                   << qt_error_string(hr);
diff --git a/src/plugins/sensors/winrt/winrtorientationsensor.cpp b/src/plugins/sensors/winrt/winrtorientationsensor.cpp
index a40dbb9d..c679d925 100644
--- a/src/plugins/sensors/winrt/winrtorientationsensor.cpp
+++ b/src/plugins/sensors/winrt/winrtorientationsensor.cpp
@@ -38,9 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QOrientationSensor>
+#include <private/qeventdispatcher_winrt_p.h>
 
-QT_USE_NAMESPACE
-
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -119,20 +119,24 @@ WinRtOrientationSensor::WinRtOrientationSensor(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtOrientationSensorPrivate(this))
 {
     Q_D(WinRtOrientationSensor);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_SimpleOrientationSensor);
-    ComPtr<ISimpleOrientationSensorStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize orientation sensor factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_SimpleOrientationSensor);
+        ComPtr<ISimpleOrientationSensorStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize orientation sensor factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default orientation sensor."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default orientation sensor."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -152,9 +156,11 @@ void WinRtOrientationSensor::start()
     if (d->token.value)
         return;
 
-    ComPtr<SimpleOrientationReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<SimpleOrientationReadingHandler> callback =
             Callback<SimpleOrientationReadingHandler>(d, &WinRtOrientationSensorPrivate::readingChanged);
-    HRESULT hr = d->sensor->add_OrientationChanged(callback.Get(), &d->token);
+        return d->sensor->add_OrientationChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -171,7 +177,9 @@ void WinRtOrientationSensor::stop()
     if (!d->token.value)
         return;
 
-    HRESULT hr = d->sensor->remove_OrientationChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_OrientationChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
diff --git a/src/plugins/sensors/winrt/winrtrotationsensor.cpp b/src/plugins/sensors/winrt/winrtrotationsensor.cpp
index 93c19b0a..570ef0bb 100644
--- a/src/plugins/sensors/winrt/winrtrotationsensor.cpp
+++ b/src/plugins/sensors/winrt/winrtrotationsensor.cpp
@@ -38,7 +38,9 @@
 #include "winrtcommon.h"
 
 #include <QtSensors/QRotationSensor>
+#include <private/qeventdispatcher_winrt_p.h>
 
+#include <functional>
 #include <wrl.h>
 #include <windows.devices.sensors.h>
 using namespace Microsoft::WRL;
@@ -109,20 +111,24 @@ WinRtRotationSensor::WinRtRotationSensor(QSensor *sensor)
     : QSensorBackend(sensor), d_ptr(new WinRtRotationSensorPrivate(this))
 {
     Q_D(WinRtRotationSensor);
-    HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Inclinometer);
-    ComPtr<IInclinometerStatics> factory;
-    HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
-    if (FAILED(hr)) {
-        qCWarning(lcWinRtSensors) << "Unable to initialize rotation sensor factory."
-                                  << qt_error_string(hr);
-        sensorError(hr);
-        return;
-    }
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        HStringReference classId(RuntimeClass_Windows_Devices_Sensors_Inclinometer);
+        ComPtr<IInclinometerStatics> factory;
+        HRESULT hr = RoGetActivationFactory(classId.Get(), IID_PPV_ARGS(&factory));
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to initialize rotation sensor factory."
+                                      << qt_error_string(hr);
+            return hr;
+        }
 
-    hr = factory->GetDefault(&d->sensor);
+        hr = factory->GetDefault(&d->sensor);
+        if (FAILED(hr)) {
+            qCWarning(lcWinRtSensors) << "Unable to get default rotation sensor."
+                                      << qt_error_string(hr);
+        }
+        return hr;
+    });
     if (FAILED(hr) || !d->sensor) {
-        qCWarning(lcWinRtSensors) << "Unable to get default rotation sensor."
-                                  << qt_error_string(hr);
         sensorError(hr);
         return;
     }
@@ -153,9 +159,11 @@ void WinRtRotationSensor::start()
     if (d->token.value)
         return;
 
-    ComPtr<InclinometerReadingHandler> callback =
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        ComPtr<InclinometerReadingHandler> callback =
             Callback<InclinometerReadingHandler>(d, &WinRtRotationSensorPrivate::readingChanged);
-    HRESULT hr = d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+        return d->sensor->add_ReadingChanged(callback.Get(), &d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to attach to reading changed event."
                                   << qt_error_string(hr);
@@ -184,14 +192,16 @@ void WinRtRotationSensor::stop()
     if (!d->token.value)
         return;
 
-    HRESULT hr = d->sensor->remove_ReadingChanged(d->token);
+    HRESULT hr = QEventDispatcherWinRT::runOnXamlThread([d]() {
+        return d->sensor->remove_ReadingChanged(d->token);
+    });
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to detach from reading changed event."
                                   << qt_error_string(hr);
         sensorError(hr);
         return;
     }
-    d->sensor->put_ReportInterval(0);
+    hr = d->sensor->put_ReportInterval(0);
     if (FAILED(hr)) {
         qCWarning(lcWinRtSensors) << "Unable to reset report interval."
                                   << qt_error_string(hr);
-- 
cgit v1.2.3