Keep the Flatpak USB permission request open; document the Loop/Shuffle stall

README.md

@@ -762,6 +762,20 @@ Add it to the kernel command line of your boot loader, reboot, and switch the
 power supply off once so the display recovers. Details and measurements are in
 issue #28.
 
+### Display stops answering during Loop or Shuffle playback
+
+With Loop or Shuffle, the runtime hands the playlist to the display, and the
+firmware switches media on its own. On a Panorama SE `391a:1021` with firmware
+v2.0.6 and a carousel of still images, the display stopped answering anywhere
+from half an hour to several hours into a session. It stays on USB but no
+longer accepts data, and the runtime reports that the keepalive stopped after
+3 retries. Restarting the runtime or rebinding the USB device does not help;
+only switching the power supply off does. One still image ran for more than
+10 hours on the same setup.
+
+Until TRYX fixes the firmware, use Single playback with one image or video.
+Details are in issue #37.
+
 ### The display session never starts after the first media upload
 
 Before 2.5.3 the runtime created its directories with permissions from the

src/portalusb.cpp

@@ -157,10 +157,12 @@ Access::Access(Registry &registry, QObject *parent) : Access(registry, Options{}
 Access::Access(Registry &registry, const Options &options, QObject *parent)
     : QObject(parent), registry_(registry), options_(options), bus_(QString()) {
     registerTypes();
-    permissionDeadline_.setSingleShot(true);
-    connect(&permissionDeadline_, &QTimer::timeout, this, [this]() {
-        logPortalEvent(QStringLiteral("acquire_timeout"));
-        fail(tr("The USB permission request timed out. Restart the Flatpak background runtime to try again."));
+    // A permission dialog that nobody answered after boot used to time out
+    // and leave the runtime without USB access until it was restarted (#37).
+    // The dialog now stays open until the user allows or denies access.
+    pendingNotice_.setSingleShot(true);
+    connect(&pendingNotice_, &QTimer::timeout, this, [this]() {
+        logPortalEvent(QStringLiteral("acquire_still_pending"));
     });
     connectionCheck_.setInterval(250);
     connect(&connectionCheck_, &QTimer::timeout, this, [this]() {
@@ -440,17 +442,15 @@ bool Access::maybeAcquire() {
         // fail() already published the terminal state.
         return true;
     }
-    permissionDeadline_.start(qMax(1, options_.permissionTimeoutMs));
+    pendingNotice_.start(qMax(1, options_.pendingNoticeMs));
     {
         QMutexLocker lock(&registry_.mutex_);
         // A new open request supersedes an earlier denial text.
         registry_.acquisitionPending_ = true;
         registry_.error_.clear();
     }
     logPortalEvent(QStringLiteral("acquire_requested"),
-                   {{QStringLiteral("product"), printerProductIdString(device.productId)},
-                    {QStringLiteral("timeout_ms"),
-                     QString::number(qMax(1, options_.permissionTimeoutMs))}});
+                   {{QStringLiteral("product"), printerProductIdString(device.productId)}});
     const QString request = requestPath_;
     call(owner_, kDesktopPath, kUsbInterface, QStringLiteral("AcquireDevices"),
          {QString(), QVariant::fromValue(Devices{{device.id, {{QStringLiteral("writable"), true}}}}),
@@ -499,7 +499,7 @@ void Access::processAcquisitionResponse(uint response) {
     logPortalEvent(QStringLiteral("acquire_response"),
                    {{QStringLiteral("code"), QString::number(response)}});
     if (response != 0) {
-        permissionDeadline_.stop();
+        pendingNotice_.stop();
         requestPath_.clear();
         pendingId_.clear();
         pendingEndpoint_.clear();
@@ -579,7 +579,7 @@ void Access::finishAcquire() {
                                     : QStringLiteral("acquire_discarded"));
             if (!accepted)
                 releaseDevices({pendingId_});
-            permissionDeadline_.stop();
+            pendingNotice_.stop();
             requestPath_.clear();
             pendingId_.clear();
             pendingEndpoint_.clear();
@@ -641,7 +641,7 @@ void Access::stop() {
     running_ = false;
     ++generation_;
     sessionReady_ = false;
-    permissionDeadline_.stop();
+    pendingNotice_.stop();
     connectionCheck_.stop();
     closeRemote(requestPath_, kRequestInterface);
     closeRemote(sessionPath_, kSessionInterface);

src/portalusb.h

@@ -87,7 +87,9 @@ class Access final : public QObject {
     struct Options {
         QString service = QStringLiteral("org.freedesktop.portal.Desktop");
         int callTimeoutMs = 2000;
-        int permissionTimeoutMs = 120000;
+        // The permission request stays open until the user answers it; after
+        // this long the runtime only logs once that it is still waiting.
+        int pendingNoticeMs = 120000;
     };
     explicit Access(Registry &registry, QObject *parent = nullptr);
     Access(Registry &registry, const Options &options, QObject *parent = nullptr);
@@ -128,7 +130,7 @@ private slots:
     QString connectionName_;
     QDBusConnection bus_;
     QDBusServiceWatcher *watcher_ = nullptr;
-    QTimer permissionDeadline_;
+    QTimer pendingNotice_;
     QTimer connectionCheck_;
     QString owner_;
     QString sessionPath_;

tests/flatpak/portalusb_tests.cpp

@@ -311,23 +311,28 @@ private slots:
         QVERIFY(!registry.snapshot().monitoring);
     }
 
-    void permissionTimeoutClosesRequestAndIgnoresLateSuccess() {
+    // An unanswered permission dialog stays open: a user who only allows
+    // access later, for example after login, still gets the device (#37).
+    void unansweredPermissionRequestStaysOpenUntilAllowed() {
         FakePortal portal;
         portal.replyAutomatically = false;
         QVERIFY(portal.install());
         Registry registry;
         Access::Options options;
-        options.permissionTimeoutMs = 100;
+        options.pendingNoticeMs = 50;
         Access access(registry, options);
         QVERIFY(access.start());
         QTRY_COMPARE(portal.acquisitions, 1);
-        QTRY_VERIFY(!registry.snapshot().error.isEmpty());
-        QTRY_VERIFY(portal.request.closed);
-        QVERIFY(!registry.snapshot().acquisitionPending);
+        QTest::qWait(200);
+        QVERIFY(!portal.request.closed);
+        QVERIFY(registry.snapshot().acquisitionPending);
+        QVERIFY(registry.snapshot().error.isEmpty());
+        QVERIFY(registry.snapshot().monitoring);
         emit portal.request.Response(0, {});
-        QTest::qWait(25);
-        QCOMPARE(portal.finishes, 0);
-        QVERIFY(!registry.snapshot().monitoring);
+        QTRY_VERIFY(registry.snapshot().devices.size() == 1 &&
+                    registry.snapshot().devices.first().granted);
+        QVERIFY(!registry.snapshot().acquisitionPending);
+        QCOMPARE(portal.acquisitions, 1);
     }
 
     void portalOwnerLossRevokesWithoutReacquiring() {
@@ -511,7 +516,7 @@ private slots:
                                 "product=\"391a:1021\" readable=\"true\" writable=\"true\" "
                                 "same_identity=\"false\" granted=\"false\"$"),
                  QStringLiteral("^tryx_usb_portal event=\"acquire_requested\" "
-                                "product=\"391a:1021\" timeout_ms=\"[0-9]+\"$"),
+                                "product=\"391a:1021\"$"),
                  QStringLiteral("^tryx_usb_portal event=\"acquire_acknowledged\"$"),
                  QStringLiteral("^tryx_usb_portal event=\"acquire_response\" code=\"0\"$"),
                  QStringLiteral("^tryx_usb_portal event=\"acquire_granted\"$"),