autotests/drm: add test for vrr capability changing without a hotunplug

autotests/drm/drmTest.cpp

@@ -7,6 +7,7 @@
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
+#include <QSignalSpy>
 #include <QSize>
 #include <QTest>
 
@@ -70,6 +71,7 @@ private Q_SLOTS:
     void testConnectorLifetime();
     void testModeset_data();
     void testModeset();
+    void testVrrChange();
 };
 
 static void verifyCleanup(MockGpu *mockGpu)
@@ -394,5 +396,32 @@ void DrmTest::testModeset()
     verifyCleanup(mockGpu.get());
 }
 
+void DrmTest::testVrrChange()
+{
+    const auto mockGpu = findPrimaryDevice(5);
+    mockGpu->deviceCaps[MOCKDRM_DEVICE_CAP_ATOMIC] = 1;
+
+    const auto conn = std::make_shared<MockConnector>(mockGpu.get());
+    conn->setVrrCapable(false);
+    mockGpu->connectors.push_back(conn);
+
+    const auto session = Session::create(Session::Type::Noop);
+    const auto backend = std::make_unique<DrmBackend>(session.get());
+    const auto renderBackend = backend->createQPainterBackend();
+    auto gpu = std::make_unique<DrmGpu>(backend.get(), mockGpu->fd, DrmDevice::open(mockGpu->devNode));
+
+    QVERIFY(gpu->updateOutputs());
+    const auto output = gpu->drmOutputs().front();
+    QVERIFY(!(output->capabilities() & Output::Capability::Vrr));
+
+    QSignalSpy capsChanged(output, &Output::capabilitiesChanged);
+
+    conn->setVrrCapable(true);
+    QVERIFY(gpu->updateOutputs());
+    QCOMPARE(gpu->drmOutputs().front(), output);
+    QCOMPARE(capsChanged.count(), 1);
+    QVERIFY(output->capabilities() & Output::Capability::Vrr);
+}
+
 QTEST_GUILESS_MAIN(DrmTest)
 #include "drmTest.moc"

autotests/drm/mock_drm.cpp

@@ -212,6 +212,14 @@ void MockConnector::addMode(uint32_t width, uint32_t height, float refreshRate,
     free(modeInfo);
 }
 
+void MockConnector::setVrrCapable(bool cap)
+{
+    auto &prop = *std::ranges::find_if(props, [](const auto &prop) {
+        return prop.name == "vrr_capable";
+    });
+    prop.value = cap ? 1 : 0;
+}
+
 //
 
 MockCrtc::MockCrtc(MockGpu *gpu, const std::shared_ptr<MockPlane> &legacyPlane, int pipeIndex, int gamma_size)

autotests/drm/mock_drm.h

@@ -71,6 +71,7 @@ public:
     ~MockConnector() = default;
 
     void addMode(uint32_t width, uint32_t height, float refreshRate, bool preferred = false);
+    void setVrrCapable(bool cap);
 
     drmModeConnection connection;
     uint32_t type;