Implement reg/unregSupportedValueChange.

Flag: EXEMPT hal
Bug: 382563296
Test: atest DefaultVehicleHalTest
Change-Id: I29fc11a0ec519f1185ac3f310f871b8e377e89b9
diff --git a/automotive/vehicle/aidl/impl/current/hardware/include/IVehicleHardware.h b/automotive/vehicle/aidl/impl/current/hardware/include/IVehicleHardware.h
index f46a1c8..9122955 100644
--- a/automotive/vehicle/aidl/impl/current/hardware/include/IVehicleHardware.h
+++ b/automotive/vehicle/aidl/impl/current/hardware/include/IVehicleHardware.h
@@ -303,6 +303,8 @@
     //
     // If the propertyId's supported values are static, then must do nothing.
     //
+    // If some of the [propId, areaId]s are already subscribed, then do nothing.
+    //
     // This is only called for [propId, areaId] that has non-null {@code HasSupportedValueInfo}.
     //
     // Client must implement (override) this function if at least one [propId, areaId]'s
diff --git a/automotive/vehicle/aidl/impl/current/vhal/include/SubscriptionManager.h b/automotive/vehicle/aidl/impl/current/vhal/include/SubscriptionManager.h
index cac1901..59c21aa 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/include/SubscriptionManager.h
+++ b/automotive/vehicle/aidl/impl/current/vhal/include/SubscriptionManager.h
@@ -118,8 +118,19 @@
                        std::vector<aidl::android::hardware::automotive::vehicle::VehiclePropError>>
     getSubscribedClientsForErrorEvents(const std::vector<SetValueErrorEvent>& errorEvents);
 
-    // Returns the number of subscribed clients.
-    size_t countClients();
+    // Subscribes to supported values change.
+    VhalResult<void> subscribeSupportedValueChange(const CallbackType& callback,
+                                                   const std::vector<PropIdAreaId>& propIdAreaIds);
+
+    // Unsubscribes to supported values change.
+    VhalResult<void> unsubscribeSupportedValueChange(
+            ClientIdType client, const std::vector<PropIdAreaId>& propIdAreaIds);
+
+    // Returns the number of subscribed property change clients.
+    size_t countPropertyChangeClients();
+
+    // Returns the number of subscribed supported value change clients.
+    size_t countSupportedValueChangeClients();
 
     // Checks whether the sample rate is valid.
     static bool checkSampleRateHz(float sampleRateHz);
@@ -160,6 +171,11 @@
                        std::unordered_set<VehiclePropValue, VehiclePropValueHashPropIdAreaId,
                                           VehiclePropValueEqualPropIdAreaId>>
             mContSubValuesByCallback GUARDED_BY(mLock);
+    std::unordered_map<PropIdAreaId, std::unordered_map<ClientIdType, CallbackType>,
+                       PropIdAreaIdHash>
+            mSupportedValueChangeClientsByPropIdAreaId GUARDED_BY(mLock);
+    std::unordered_map<ClientIdType, std::unordered_set<PropIdAreaId, PropIdAreaIdHash>>
+            mSupportedValueChangePropIdAreaIdsByClient GUARDED_BY(mLock);
 
     VhalResult<void> addContinuousSubscriberLocked(const ClientIdType& clientId,
                                                    const PropIdAreaId& propIdAreaId,
@@ -180,6 +196,9 @@
     VhalResult<void> unsubscribePropIdAreaIdLocked(SubscriptionManager::ClientIdType clientId,
                                                    const PropIdAreaId& propIdAreaId)
             REQUIRES(mLock);
+    VhalResult<void> unsubscribeSupportedValueChangeLocked(
+            SubscriptionManager::ClientIdType clientId,
+            const std::vector<PropIdAreaId>& propIdAreaIds) REQUIRES(mLock);
 
     // Checks whether the manager is empty. For testing purpose.
     bool isEmpty();
diff --git a/automotive/vehicle/aidl/impl/current/vhal/src/DefaultVehicleHal.cpp b/automotive/vehicle/aidl/impl/current/vhal/src/DefaultVehicleHal.cpp
index 509d1c3..9073d85 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/src/DefaultVehicleHal.cpp
+++ b/automotive/vehicle/aidl/impl/current/vhal/src/DefaultVehicleHal.cpp
@@ -82,9 +82,6 @@
 
 using VhalPropIdAreaId = ::aidl::android::hardware::automotive::vehicle::PropIdAreaId;
 
-#define propIdtoString(PROP_ID) \
-    aidl::android::hardware::automotive::vehicle::toString(static_cast<VehicleProperty>(PROP_ID))
-
 std::string toString(const std::unordered_set<int64_t>& values) {
     std::string str = "";
     for (auto it = values.begin(); it != values.end(); it++) {
@@ -976,13 +973,13 @@
         int32_t propId, int32_t areaId) const {
     auto result = getConfig(propId);
     if (!result.ok()) {
-        return Error() << "Failed to get property config for propertyId: " << propIdtoString(propId)
+        return Error() << "Failed to get property config for propertyId: " << propIdToString(propId)
                        << ", error: " << result.error();
     }
     const VehiclePropConfig& config = result.value();
     const VehicleAreaConfig* areaConfig = getAreaConfig(propId, areaId, config);
     if (areaConfig == nullptr) {
-        return Error() << "AreaId config not found for propertyId: " << propIdtoString(propId)
+        return Error() << "AreaId config not found for propertyId: " << propIdToString(propId)
                        << ", areaId: " << areaId;
     }
     return areaConfig;
@@ -1002,7 +999,7 @@
             return &(areaConfig->hasSupportedValueInfo.value());
         }
     }
-    return Error() << "property: " << propIdtoString(propId) << ", areaId: " << areaId
+    return Error() << "property: " << propIdToString(propId) << ", areaId: " << areaId
                    << " does not support this operation because hasSupportedValueInfo is null";
 }
 
@@ -1130,15 +1127,65 @@
 }
 
 ScopedAStatus DefaultVehicleHal::registerSupportedValueChangeCallback(
-        const std::shared_ptr<IVehicleCallback>&, const std::vector<VhalPropIdAreaId>&) {
-    // TODO(b/381020465): Add relevant implementation.
-    return ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+        const std::shared_ptr<IVehicleCallback>& callback,
+        const std::vector<VhalPropIdAreaId>& vhalPropIdAreaIds) {
+    std::vector<PropIdAreaId> propIdAreaIdsToSubscribe;
+    for (size_t i = 0; i < vhalPropIdAreaIds.size(); i++) {
+        const auto& vhalPropIdAreaId = vhalPropIdAreaIds.at(i);
+        int32_t propId = vhalPropIdAreaId.propId;
+        int32_t areaId = vhalPropIdAreaId.areaId;
+        auto hasSupportedValueInfoResult = getHasSupportedValueInfo(propId, areaId);
+        if (!hasSupportedValueInfoResult.ok()) {
+            ALOGE("registerSupportedValueChangeCallback not supported: %s",
+                  hasSupportedValueInfoResult.error().message().c_str());
+            return toScopedAStatus(hasSupportedValueInfoResult, StatusCode::INVALID_ARG);
+        }
+        const auto& hasSupportedValueInfo = *(hasSupportedValueInfoResult.value());
+        if (!hasSupportedValueInfo.hasMinSupportedValue &&
+            !hasSupportedValueInfo.hasMaxSupportedValue &&
+            !hasSupportedValueInfo.hasSupportedValuesList) {
+            ALOGW("registerSupportedValueChangeCallback: do nothing for property: %s, "
+                  "areaId: %" PRId32
+                  ", no min/max supported values or supported values list"
+                  " specified",
+                  propIdToString(propId).c_str(), areaId);
+            continue;
+        }
+        propIdAreaIdsToSubscribe.push_back(PropIdAreaId{.propId = propId, .areaId = areaId});
+    }
+    if (propIdAreaIdsToSubscribe.empty()) {
+        return ScopedAStatus::ok();
+    }
+    auto result =
+            mSubscriptionManager->subscribeSupportedValueChange(callback, propIdAreaIdsToSubscribe);
+    if (!result.ok()) {
+        ALOGW("registerSupportedValueChangeCallback: failed to subscribe supported value change"
+              " for %s, error: %s",
+              fmt::format("{}", propIdAreaIdsToSubscribe).c_str(),
+              result.error().message().c_str());
+        return toScopedAStatus(result);
+    }
+    return ScopedAStatus::ok();
 }
 
 ScopedAStatus DefaultVehicleHal::unregisterSupportedValueChangeCallback(
-        const std::shared_ptr<IVehicleCallback>&, const std::vector<VhalPropIdAreaId>&) {
-    // TODO(b/381020465): Add relevant implementation.
-    return ScopedAStatus::fromExceptionCode(EX_UNSUPPORTED_OPERATION);
+        const std::shared_ptr<IVehicleCallback>& callback,
+        const std::vector<VhalPropIdAreaId>& vhalPropIdAreaIds) {
+    std::vector<PropIdAreaId> propIdAreaIds;
+    for (const auto& vhalPropIdAreaId : vhalPropIdAreaIds) {
+        propIdAreaIds.push_back(
+                PropIdAreaId{.propId = vhalPropIdAreaId.propId, .areaId = vhalPropIdAreaId.areaId});
+    }
+
+    auto result = mSubscriptionManager->unsubscribeSupportedValueChange(callback->asBinder().get(),
+                                                                        propIdAreaIds);
+    if (!result.ok()) {
+        ALOGW("unregisterSupportedValueChangeCallback: failed to unsubscribe supported value change"
+              " for %s, error: %s",
+              fmt::format("{}", propIdAreaIds).c_str(), result.error().message().c_str());
+        return toScopedAStatus(result);
+    }
+    return ScopedAStatus::ok();
 }
 
 IVehicleHardware* DefaultVehicleHal::getHardware() {
@@ -1256,12 +1303,14 @@
         dprintf(fd, "Currently have %zu getValues clients\n", mGetValuesClients.size());
         dprintf(fd, "Currently have %zu setValues clients\n", mSetValuesClients.size());
         dprintf(fd, "Currently have %zu subscribe clients\n", countSubscribeClients());
+        dprintf(fd, "Currently have %zu supported values change subscribe clients\n",
+                mSubscriptionManager->countSupportedValueChangeClients());
     }
     return STATUS_OK;
 }
 
 size_t DefaultVehicleHal::countSubscribeClients() {
-    return mSubscriptionManager->countClients();
+    return mSubscriptionManager->countPropertyChangeClients();
 }
 
 }  // namespace vehicle
diff --git a/automotive/vehicle/aidl/impl/current/vhal/src/SubscriptionManager.cpp b/automotive/vehicle/aidl/impl/current/vhal/src/SubscriptionManager.cpp
index 2d09e02..f790033 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/src/SubscriptionManager.cpp
+++ b/automotive/vehicle/aidl/impl/current/vhal/src/SubscriptionManager.cpp
@@ -17,6 +17,7 @@
 #include "SubscriptionManager.h"
 
 #include <VehicleUtils.h>
+#include <android-base/format.h>
 #include <android-base/stringprintf.h>
 #include <utils/Log.h>
 #include <utils/SystemClock.h>
@@ -65,6 +66,8 @@
 
     mClientsByPropIdAreaId.clear();
     mSubscribedPropsByClient.clear();
+    mSupportedValueChangeClientsByPropIdAreaId.clear();
+    mSupportedValueChangePropIdAreaIdsByClient.clear();
 }
 
 bool SubscriptionManager::checkSampleRateHz(float sampleRateHz) {
@@ -166,8 +169,7 @@
                                     /*enableVur*/ false));
         status != StatusCode::OK) {
         return StatusError(status)
-               << StringPrintf("failed subscribe for prop: %s, areaId: %" PRId32,
-                               propIdToString(propId).c_str(), areaId);
+               << fmt::format("failed subscribe for propIdAreaId: {}", propIdAreaId);
     }
     return {};
 }
@@ -379,16 +381,111 @@
 
     if (mSubscribedPropsByClient.find(clientId) == mSubscribedPropsByClient.end()) {
         ALOGW("No property was subscribed for this client, unsubscribe does nothing");
-        return {};
+    } else {
+        auto& propIdAreaIds = mSubscribedPropsByClient[clientId];
+        for (auto const& propIdAreaId : propIdAreaIds) {
+            if (auto result = unsubscribePropIdAreaIdLocked(clientId, propIdAreaId); !result.ok()) {
+                return result;
+            }
+        }
+        mSubscribedPropsByClient.erase(clientId);
     }
 
-    auto& subscriptions = mSubscribedPropsByClient[clientId];
-    for (auto const& propIdAreaId : subscriptions) {
-        if (auto result = unsubscribePropIdAreaIdLocked(clientId, propIdAreaId); !result.ok()) {
+    if (mSupportedValueChangePropIdAreaIdsByClient.find(clientId) ==
+        mSupportedValueChangePropIdAreaIdsByClient.end()) {
+        ALOGW("No supported value change was subscribed for this client, unsubscribe does nothing");
+    } else {
+        const auto& propIdAreaIds = mSupportedValueChangePropIdAreaIdsByClient[clientId];
+        if (auto result = unsubscribeSupportedValueChangeLocked(
+                    clientId,
+                    std::vector<PropIdAreaId>(propIdAreaIds.begin(), propIdAreaIds.end()));
+            !result.ok()) {
             return result;
         }
     }
-    mSubscribedPropsByClient.erase(clientId);
+    return {};
+}
+
+VhalResult<void> SubscriptionManager::subscribeSupportedValueChange(
+        const std::shared_ptr<IVehicleCallback>& callback,
+        const std::vector<PropIdAreaId>& propIdAreaIds) {
+    // Need to make sure this whole operation is guarded by a lock so that our internal state is
+    // consistent with IVehicleHardware state.
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    ClientIdType clientId = callback->asBinder().get();
+
+    // It is possible that some of the [propId, areaId]s are already subscribed, IVehicleHardware
+    // will ignore them.
+    if (auto status = mVehicleHardware->subscribeSupportedValueChange(propIdAreaIds);
+        status != StatusCode::OK) {
+        return StatusError(status)
+               << fmt::format("failed to call subscribeSupportedValueChange for propIdAreaIds: {}",
+                              propIdAreaIds);
+    }
+    for (const auto& propIdAreaId : propIdAreaIds) {
+        mSupportedValueChangeClientsByPropIdAreaId[propIdAreaId][clientId] = callback;
+        // mSupportedValueChangePropIdAreaIdsByClient[clientId] is a set so this will ignore
+        // duplicate [propId, areaId].
+        mSupportedValueChangePropIdAreaIdsByClient[clientId].insert(propIdAreaId);
+    }
+    return {};
+}
+
+VhalResult<void> SubscriptionManager::unsubscribeSupportedValueChange(
+        SubscriptionManager::ClientIdType clientId,
+        const std::vector<PropIdAreaId>& propIdAreaIds) {
+    // Need to make sure this whole operation is guarded by a lock so that our internal state is
+    // consistent with IVehicleHardware state.
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+
+    return unsubscribeSupportedValueChangeLocked(clientId, propIdAreaIds);
+}
+
+VhalResult<void> SubscriptionManager::unsubscribeSupportedValueChangeLocked(
+        SubscriptionManager::ClientIdType clientId,
+        const std::vector<PropIdAreaId>& propIdAreaIds) {
+    std::vector<PropIdAreaId> propIdAreaIdsToUnsubscribe;
+
+    // Check which [propId, areaId] needs to be unsubscribed from the hardware.
+    for (const auto& propIdAreaId : propIdAreaIds) {
+        auto it = mSupportedValueChangeClientsByPropIdAreaId.find(propIdAreaId);
+        if (it != mSupportedValueChangeClientsByPropIdAreaId.end()) {
+            const auto& clients = it->second;
+            if (clients.size() == 1 && clients.find(clientId) != clients.end()) {
+                // This callback is the only client registered for [propId, areaId].
+                // Unregister it should unregister the [propId, areaId].
+                propIdAreaIdsToUnsubscribe.push_back(propIdAreaId);
+            }
+        }
+    }
+
+    // Send the unsubscribe request.
+    if (!propIdAreaIdsToUnsubscribe.empty()) {
+        if (auto status =
+                    mVehicleHardware->unsubscribeSupportedValueChange(propIdAreaIdsToUnsubscribe);
+            status != StatusCode::OK) {
+            return StatusError(status) << fmt::format(
+                           "failed to call unsubscribeSupportedValueChange for "
+                           "propIdAreaIds: {}",
+                           propIdAreaIdsToUnsubscribe);
+        }
+    }
+
+    // Remove internal book-keeping.
+    for (const auto& propIdAreaId : propIdAreaIds) {
+        if (mSupportedValueChangeClientsByPropIdAreaId.find(propIdAreaId) !=
+            mSupportedValueChangeClientsByPropIdAreaId.end()) {
+            mSupportedValueChangeClientsByPropIdAreaId[propIdAreaId].erase(clientId);
+        }
+        if (mSupportedValueChangeClientsByPropIdAreaId.empty()) {
+            mSupportedValueChangeClientsByPropIdAreaId.erase(propIdAreaId);
+        }
+        mSupportedValueChangePropIdAreaIdsByClient[clientId].erase(propIdAreaId);
+        if (mSupportedValueChangePropIdAreaIdsByClient[clientId].empty()) {
+            mSupportedValueChangePropIdAreaIdsByClient.erase(clientId);
+        }
+    }
     return {};
 }
 
@@ -486,14 +583,21 @@
 
 bool SubscriptionManager::isEmpty() {
     std::scoped_lock<std::mutex> lockGuard(mLock);
-    return mSubscribedPropsByClient.empty() && mClientsByPropIdAreaId.empty();
+    return mSubscribedPropsByClient.empty() && mClientsByPropIdAreaId.empty() &&
+           mSupportedValueChangeClientsByPropIdAreaId.empty() &&
+           mSupportedValueChangePropIdAreaIdsByClient.empty();
 }
 
-size_t SubscriptionManager::countClients() {
+size_t SubscriptionManager::countPropertyChangeClients() {
     std::scoped_lock<std::mutex> lockGuard(mLock);
     return mSubscribedPropsByClient.size();
 }
 
+size_t SubscriptionManager::countSupportedValueChangeClients() {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+    return mSupportedValueChangePropIdAreaIdsByClient.size();
+}
+
 }  // namespace vehicle
 }  // namespace automotive
 }  // namespace hardware
diff --git a/automotive/vehicle/aidl/impl/current/vhal/test/DefaultVehicleHalTest.cpp b/automotive/vehicle/aidl/impl/current/vhal/test/DefaultVehicleHalTest.cpp
index 4df5ba3..0526f7d 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/test/DefaultVehicleHalTest.cpp
+++ b/automotive/vehicle/aidl/impl/current/vhal/test/DefaultVehicleHalTest.cpp
@@ -2418,6 +2418,205 @@
     ASSERT_EQ(result.status, StatusCode::INVALID_ARG);
 }
 
+TEST_F(DefaultVehicleHalTest, testRegisterSupportedValueChangeCallback) {
+    auto testConfigs = std::vector<VehiclePropConfig>(
+            {VehiclePropConfig{
+                     .prop = testInt32VecProp(1),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 0,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = false,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = false,
+                                              }},
+                             },
+             },
+             VehiclePropConfig{
+                     .prop = testInt32VecWindowProp(2),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 2,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = true,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = false,
+                                              }},
+                             },
+             }});
+
+    auto hardware = std::make_unique<MockVehicleHardware>();
+    MockVehicleHardware* hardwarePtr = hardware.get();
+    hardware->setPropertyConfigs(testConfigs);
+
+    auto vhal = ndk::SharedRefBase::make<DefaultVehicleHal>(std::move(hardware));
+    std::shared_ptr<IVehicle> client = IVehicle::fromBinder(vhal->asBinder());
+
+    // This request is ignored because it does not have supported value info.
+    auto propIdAreaId1 = VhalPropIdAreaId{.propId = testInt32VecProp(1), .areaId = 0};
+    auto propIdAreaId2 = VhalPropIdAreaId{.propId = testInt32VecWindowProp(2), .areaId = 2};
+    auto status = client->registerSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId1, propIdAreaId2});
+
+    ASSERT_TRUE(status.isOk()) << "Get non-okay status from registerSupportedValueChangeCallback"
+                               << status.getMessage();
+    ASSERT_THAT(hardwarePtr->getSubscribedSupportedValueChangePropIdAreaIds(),
+                ElementsAre(PropIdAreaId{.propId = testInt32VecWindowProp(2), .areaId = 2}));
+}
+
+TEST_F(DefaultVehicleHalTest, testRegisterSupportedValueChangeCallback_invalidRequest) {
+    auto testConfigs = std::vector<VehiclePropConfig>({VehiclePropConfig{
+            .prop = testInt32VecProp(1),
+            .areaConfigs =
+                    {
+                            {.areaId = 0, .hasSupportedValueInfo = std::nullopt},
+                    },
+    }});
+    auto hardware = std::make_unique<MockVehicleHardware>();
+    hardware->setPropertyConfigs(testConfigs);
+
+    auto vhal = ndk::SharedRefBase::make<DefaultVehicleHal>(std::move(hardware));
+    std::shared_ptr<IVehicle> client = IVehicle::fromBinder(vhal->asBinder());
+
+    auto propIdAreaId1 = VhalPropIdAreaId{.propId = testInt32VecProp(1), .areaId = 0};
+    auto status = client->registerSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId1});
+
+    ASSERT_FALSE(status.isOk()) << "registerSupportedValueChangeCallback must return error if one "
+                                   "of the requested [propId, areaId]"
+                                   " does not have supportedValueInfo";
+}
+
+TEST_F(DefaultVehicleHalTest, testRegisterSupportedValueChangeCallback_errorStatusFromHardware) {
+    auto testConfigs = std::vector<VehiclePropConfig>({VehiclePropConfig{
+            .prop = testInt32VecWindowProp(2),
+            .areaConfigs =
+                    {
+                            {.areaId = 2,
+                             .hasSupportedValueInfo =
+                                     HasSupportedValueInfo{
+                                             .hasMinSupportedValue = true,
+                                             .hasMaxSupportedValue = false,
+                                             .hasSupportedValuesList = false,
+                                     }},
+                    },
+    }});
+
+    auto hardware = std::make_unique<MockVehicleHardware>();
+    hardware->setStatus("subscribeSupportedValueChange", StatusCode::INTERNAL_ERROR);
+    hardware->setPropertyConfigs(testConfigs);
+
+    auto vhal = ndk::SharedRefBase::make<DefaultVehicleHal>(std::move(hardware));
+    std::shared_ptr<IVehicle> client = IVehicle::fromBinder(vhal->asBinder());
+
+    auto propIdAreaId = VhalPropIdAreaId{.propId = testInt32VecWindowProp(2), .areaId = 2};
+    auto status = client->registerSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId});
+
+    ASSERT_FALSE(status.isOk()) << "registerSupportedValueChangeCallback must return error if "
+                                   "VehicleHardware returns error";
+}
+
+TEST_F(DefaultVehicleHalTest, testUnregisterSupportedValueChangeCallback) {
+    auto testConfigs = std::vector<VehiclePropConfig>(
+            {VehiclePropConfig{
+                     .prop = testInt32VecProp(1),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 0,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = false,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = true,
+                                              }},
+                             },
+             },
+             VehiclePropConfig{
+                     .prop = testInt32VecWindowProp(2),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 2,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = true,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = false,
+                                              }},
+                             },
+             }});
+
+    auto hardware = std::make_unique<MockVehicleHardware>();
+    MockVehicleHardware* hardwarePtr = hardware.get();
+    hardware->setPropertyConfigs(testConfigs);
+
+    auto vhal = ndk::SharedRefBase::make<DefaultVehicleHal>(std::move(hardware));
+    std::shared_ptr<IVehicle> client = IVehicle::fromBinder(vhal->asBinder());
+
+    auto propIdAreaId1 = VhalPropIdAreaId{.propId = testInt32VecProp(1), .areaId = 0};
+    auto propIdAreaId2 = VhalPropIdAreaId{.propId = testInt32VecWindowProp(2), .areaId = 2};
+    auto status = client->registerSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId1, propIdAreaId2});
+
+    ASSERT_TRUE(status.isOk()) << "Get non-okay status from registerSupportedValueChangeCallback"
+                               << status.getMessage();
+
+    status = client->unregisterSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId1, propIdAreaId2});
+
+    ASSERT_TRUE(status.isOk()) << "Get non-okay status from unregisterSupportedValueChangeCallback"
+                               << status.getMessage();
+
+    ASSERT_TRUE(hardwarePtr->getSubscribedSupportedValueChangePropIdAreaIds().empty())
+            << "All registered [propId, areaId]s must be unregistered";
+}
+
+TEST_F(DefaultVehicleHalTest, testUnregisterSupportedValueChangeCallback_ignoreUnregistered) {
+    auto testConfigs = std::vector<VehiclePropConfig>(
+            {VehiclePropConfig{
+                     .prop = testInt32VecProp(1),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 0,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = false,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = true,
+                                              }},
+                             },
+             },
+             VehiclePropConfig{
+                     .prop = testInt32VecWindowProp(2),
+                     .areaConfigs =
+                             {
+                                     {.areaId = 2,
+                                      .hasSupportedValueInfo =
+                                              HasSupportedValueInfo{
+                                                      .hasMinSupportedValue = true,
+                                                      .hasMaxSupportedValue = false,
+                                                      .hasSupportedValuesList = false,
+                                              }},
+                             },
+             }});
+
+    auto hardware = std::make_unique<MockVehicleHardware>();
+    MockVehicleHardware* hardwarePtr = hardware.get();
+    hardware->setPropertyConfigs(testConfigs);
+
+    auto vhal = ndk::SharedRefBase::make<DefaultVehicleHal>(std::move(hardware));
+    std::shared_ptr<IVehicle> client = IVehicle::fromBinder(vhal->asBinder());
+
+    auto propIdAreaId1 = VhalPropIdAreaId{.propId = testInt32VecProp(1), .areaId = 0};
+    auto propIdAreaId2 = VhalPropIdAreaId{.propId = testInt32VecWindowProp(2), .areaId = 2};
+    auto status = client->unregisterSupportedValueChangeCallback(
+            getCallbackClient(), std::vector<VhalPropIdAreaId>{propIdAreaId1, propIdAreaId2});
+
+    ASSERT_TRUE(status.isOk());
+}
+
 }  // namespace vehicle
 }  // namespace automotive
 }  // namespace hardware
diff --git a/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.cpp b/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.cpp
index ae2b5a2..11f1835 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.cpp
+++ b/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.cpp
@@ -310,6 +310,40 @@
     return mEventBatchingWindow;
 }
 
+StatusCode MockVehicleHardware::subscribeSupportedValueChange(
+        const std::vector<PropIdAreaId>& propIdAreaIds) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+    if (auto it = mStatusByFunctions.find(__func__); it != mStatusByFunctions.end()) {
+        if (StatusCode status = it->second; status != StatusCode::OK) {
+            return status;
+        }
+    }
+    for (const auto& propIdAreaId : propIdAreaIds) {
+        mSubscribedSupportedValueChangePropIdAreaIds.insert(propIdAreaId);
+    }
+    return StatusCode::OK;
+}
+
+StatusCode MockVehicleHardware::unsubscribeSupportedValueChange(
+        const std::vector<PropIdAreaId>& propIdAreaIds) {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+    if (auto it = mStatusByFunctions.find(__func__); it != mStatusByFunctions.end()) {
+        if (StatusCode status = it->second; status != StatusCode::OK) {
+            return status;
+        }
+    }
+    for (const auto& propIdAreaId : propIdAreaIds) {
+        mSubscribedSupportedValueChangePropIdAreaIds.erase(propIdAreaId);
+    }
+    return StatusCode::OK;
+}
+
+std::unordered_set<PropIdAreaId, PropIdAreaIdHash>
+MockVehicleHardware::getSubscribedSupportedValueChangePropIdAreaIds() {
+    std::scoped_lock<std::mutex> lockGuard(mLock);
+    return mSubscribedSupportedValueChangePropIdAreaIds;
+}
+
 template <class ResultType>
 StatusCode MockVehicleHardware::returnResponse(
         std::shared_ptr<const std::function<void(std::vector<ResultType>)>> callback,
diff --git a/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.h b/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.h
index d1e9771..e7359db 100644
--- a/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.h
+++ b/automotive/vehicle/aidl/impl/current/vhal/test/MockVehicleHardware.h
@@ -71,6 +71,10 @@
     getSupportedValuesLists(const std::vector<PropIdAreaId>& propIdAreaIds) override;
     std::vector<aidl::android::hardware::automotive::vehicle::MinMaxSupportedValueResult>
     getMinMaxSupportedValues(const std::vector<PropIdAreaId>& propIdAreaIds) override;
+    aidl::android::hardware::automotive::vehicle::StatusCode subscribeSupportedValueChange(
+            const std::vector<PropIdAreaId>& propIdAreaIds) override;
+    aidl::android::hardware::automotive::vehicle::StatusCode unsubscribeSupportedValueChange(
+            const std::vector<PropIdAreaId>& propIdAreaIds) override;
 
     // Test functions.
     void setPropertyConfigs(
@@ -114,10 +118,13 @@
     std::vector<aidl::android::hardware::automotive::vehicle::SubscribeOptions>
     getSubscribeOptions();
     void clearSubscribeOptions();
-    // Whether getAllPropertyConfigs() has been called, which blocks all all property configs
+    // Whether getAllPropertyConfigs() has been called, which blocks on all property configs
     // being ready.
     bool getAllPropertyConfigsCalled();
 
+    std::unordered_set<PropIdAreaId, PropIdAreaIdHash>
+    getSubscribedSupportedValueChangePropIdAreaIds();
+
   private:
     mutable std::mutex mLock;
     mutable std::condition_variable mCv;
@@ -174,6 +181,9 @@
     std::shared_ptr<RecurrentTimer> mRecurrentTimer;
     std::unordered_map<int32_t, std::unordered_map<int32_t, std::shared_ptr<std::function<void()>>>>
             mRecurrentActions GUARDED_BY(mLock);
+
+    std::unordered_set<PropIdAreaId, PropIdAreaIdHash> mSubscribedSupportedValueChangePropIdAreaIds
+            GUARDED_BY(mLock);
 };
 
 }  // namespace vehicle