Add plumbing for ADPF FMQ

This patch adds plumbing for ADPF to work with FMQ, including new
getSessionChannel and closeSessionChannel methods in HintManagerService.
It also introduces a system to cache FMQ descriptors per app and track
binder tokens provided by getSessionChannel, to close the FMQ channels
when the clients die.

Bug: 315894228
Test: atest HintManagerServiceTest
Change-Id: I74a8f9d679eae4c04894cdde3f2538825ec8675b

core/java/android/os/IHintManager.aidl

@@ -18,6 +18,7 @@
 package android.os;
 
 import android.os.IHintSession;
+import android.hardware.power.ChannelConfig;
 import android.hardware.power.SessionConfig;
 import android.hardware.power.SessionTag;
 
@@ -27,6 +28,9 @@ interface IHintManager {
      * Creates a {@link Session} for the given set of threads and associates to a binder token.
      * Returns a config if creation is not supported, and HMS had to use the
      * legacy creation method.
+     *
+     * Throws UnsupportedOperationException if ADPF is not supported, and IllegalStateException
+     * if creation is supported but fails.
      */
     IHintSession createHintSessionWithConfig(in IBinder token, in int[] threadIds,
             in long durationNanos, in SessionTag tag, out @nullable SessionConfig config);
@@ -38,4 +42,12 @@ interface IHintManager {
 
     void setHintSessionThreads(in IHintSession hintSession, in int[] tids);
     int[] getHintSessionThreadIds(in IHintSession hintSession);
+
+    /**
+     * Returns FMQ channel information for the caller, which it associates to a binder token.
+     *
+     * Throws IllegalStateException if FMQ channel creation fails.
+     */
+    ChannelConfig getSessionChannel(in IBinder token);
+    oneway void closeSessionChannel();
 }

native/android/tests/performance_hint/PerformanceHintNativeTest.cpp

@@ -16,6 +16,7 @@
 
 #define LOG_TAG "PerformanceHintNativeTest"
 
+#include <aidl/android/hardware/power/ChannelConfig.h>
 #include <aidl/android/hardware/power/SessionConfig.h>
 #include <aidl/android/hardware/power/SessionTag.h>
 #include <aidl/android/hardware/power/WorkDuration.h>
@@ -54,6 +55,9 @@ public:
     MOCK_METHOD(ScopedAStatus, getHintSessionThreadIds,
                 (const std::shared_ptr<IHintSession>& hintSession, ::std::vector<int32_t>* tids),
                 (override));
+    MOCK_METHOD(ScopedAStatus, getSessionChannel,
+                (const ::ndk::SpAIBinder& in_token, hal::ChannelConfig* _aidl_return), (override));
+    MOCK_METHOD(ScopedAStatus, closeSessionChannel, (), (override));
     MOCK_METHOD(SpAIBinder, asBinder, (), (override));
     MOCK_METHOD(bool, isRemote, (), (override));
 };

services/core/java/com/android/server/power/hint/HintManagerService.java

@@ -16,6 +16,8 @@
 
 package com.android.server.power.hint;
 
+import static android.os.Flags.adpfUseFmqChannel;
+
 import static com.android.internal.util.ConcurrentUtils.DIRECT_EXECUTOR;
 import static com.android.server.power.hint.Flags.powerhintThreadCleanup;
 
@@ -26,6 +28,8 @@ import android.app.ActivityManagerInternal;
 import android.app.StatsManager;
 import android.app.UidObserver;
 import android.content.Context;
+import android.hardware.power.ChannelConfig;
+import android.hardware.power.IPower;
 import android.hardware.power.SessionConfig;
 import android.hardware.power.SessionTag;
 import android.hardware.power.WorkDuration;
@@ -39,6 +43,7 @@ import android.os.Message;
 import android.os.PerformanceHintManager;
 import android.os.Process;
 import android.os.RemoteException;
+import android.os.ServiceManager;
 import android.os.SystemProperties;
 import android.text.TextUtils;
 import android.util.ArrayMap;
@@ -69,6 +74,7 @@ import java.util.Map;
 import java.util.NoSuchElementException;
 import java.util.Objects;
 import java.util.Set;
+import java.util.TreeMap;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -91,9 +97,21 @@ public final class HintManagerService extends SystemService {
     @GuardedBy("mLock")
     private final ArrayMap<Integer, ArrayMap<IBinder, ArraySet<AppHintSession>>> mActiveSessions;
 
+    // Multi-level map storing all the channel binder token death listeners.
+    // First level is keyed by the UID of the client process owning the channel.
+    // Second level is the tgid of the process, which will often just be size one.
+    // Each channel is unique per (tgid, uid) pair, so this map associates each pair with an
+    // object that listens for the death notification of the binder token that was provided by
+    // that client when it created the channel, so we can detect when the client process dies.
+    @GuardedBy("mChannelMapLock")
+    private ArrayMap<Integer, TreeMap<Integer, ChannelItem>> mChannelMap;
+
     /** Lock to protect mActiveSessions and the UidObserver. */
     private final Object mLock = new Object();
 
+    /** Lock to protect mChannelMap. */
+    private final Object mChannelMapLock = new Object();
+
     @GuardedBy("mNonIsolatedTidsLock")
     private final Map<Integer, Set<Long>> mNonIsolatedTids;
 
@@ -110,6 +128,9 @@ public final class HintManagerService extends SystemService {
 
     private AtomicBoolean mConfigCreationSupport = new AtomicBoolean(true);
 
+    private final IPower mPowerHal;
+    private int mPowerHalVersion;
+
     private static final String PROPERTY_SF_ENABLE_CPU_HINT = "debug.sf.enable_adpf_cpu_hint";
     private static final String PROPERTY_HWUI_ENABLE_HINT_MANAGER = "debug.hwui.use_hint_manager";
 
@@ -131,12 +152,22 @@ public final class HintManagerService extends SystemService {
             mNonIsolatedTids = null;
         }
         mActiveSessions = new ArrayMap<>();
+        mChannelMap = new ArrayMap<>();
         mNativeWrapper = injector.createNativeWrapper();
         mNativeWrapper.halInit();
         mHintSessionPreferredRate = mNativeWrapper.halGetHintSessionPreferredRate();
         mUidObserver = new MyUidObserver();
         mAmInternal = Objects.requireNonNull(
                 LocalServices.getService(ActivityManagerInternal.class));
+        mPowerHal = injector.createIPower();
+        mPowerHalVersion = 0;
+        if (mPowerHal != null) {
+            try {
+                mPowerHalVersion = mPowerHal.getInterfaceVersion();
+            } catch (RemoteException e) {
+                throw new IllegalStateException("Could not contact PowerHAL!", e);
+            }
+        }
     }
 
     private ServiceThread createCleanUpThread() {
@@ -151,6 +182,10 @@ public final class HintManagerService extends SystemService {
         NativeWrapper createNativeWrapper() {
             return new NativeWrapper();
         }
+        IPower createIPower() {
+            return IPower.Stub.asInterface(
+                ServiceManager.waitForDeclaredService(IPower.DESCRIPTOR + "/default"));
+        }
     }
 
     private boolean isHalSupported() {
@@ -344,6 +379,16 @@ public final class HintManagerService extends SystemService {
                         }
                     }
                 }
+                synchronized (mChannelMapLock) {
+                    // Clean up the uid's session channels
+                    final TreeMap<Integer, ChannelItem> uidMap = mChannelMap.get(uid);
+                    if (uidMap != null) {
+                        for (Map.Entry<Integer, ChannelItem> entry : uidMap.entrySet()) {
+                            entry.getValue().closeChannel();
+                        }
+                        mChannelMap.remove(uid);
+                    }
+                }
             });
         }
 
@@ -383,6 +428,113 @@ public final class HintManagerService extends SystemService {
         }
     }
 
+    /**
+     * Creates a channel item in the channel map if one does not exist, then returns
+     * the entry in the channel map.
+     */
+    public ChannelItem getOrCreateMappedChannelItem(int tgid, int uid, IBinder token) {
+        synchronized (mChannelMapLock) {
+            if (!mChannelMap.containsKey(uid)) {
+                mChannelMap.put(uid, new TreeMap<Integer, ChannelItem>());
+            }
+            TreeMap<Integer, ChannelItem> map = mChannelMap.get(uid);
+            if (!map.containsKey(tgid)) {
+                ChannelItem item = new ChannelItem(tgid, uid, token);
+                item.openChannel();
+                map.put(tgid, item);
+            }
+            return map.get(tgid);
+        }
+    }
+
+    /**
+     * This removes an entry in the binder token callback map when a channel is closed,
+     * and unregisters its callbacks.
+     */
+    public void removeChannelItem(Integer tgid, Integer uid) {
+        synchronized (mChannelMapLock) {
+            TreeMap<Integer, ChannelItem> map = mChannelMap.get(uid);
+            if (map != null) {
+                ChannelItem item = map.get(tgid);
+                if (item != null) {
+                    item.closeChannel();
+                    map.remove(tgid);
+                }
+                if (map.isEmpty()) {
+                    mChannelMap.remove(uid);
+                }
+            }
+        }
+    }
+
+    /**
+     * Manages the lifecycle of a single channel. This includes caching the channel descriptor,
+     * receiving binder token death notifications, and handling cleanup on uid termination. There
+     * can only be one ChannelItem per (tgid, uid) pair in mChannelMap, and channel creation happens
+     * when a ChannelItem enters the map, while destruction happens when it leaves the map.
+     */
+    private class ChannelItem implements IBinder.DeathRecipient {
+        @Override
+        public void binderDied() {
+            removeChannelItem(mTgid, mUid);
+        }
+
+        ChannelItem(int tgid, int uid, IBinder token) {
+            this.mTgid = tgid;
+            this.mUid = uid;
+            this.mToken = token;
+            this.mLinked = false;
+            this.mConfig = null;
+        }
+
+        public void closeChannel() {
+            if (mLinked) {
+                mToken.unlinkToDeath(this, 0);
+                mLinked = false;
+            }
+            if (mConfig != null) {
+                try  {
+                    mPowerHal.closeSessionChannel(mTgid, mUid);
+                } catch (RemoteException e) {
+                    throw new IllegalStateException("Failed to close session channel!", e);
+                }
+                mConfig = null;
+            }
+        }
+
+        public void openChannel() {
+            if (!mLinked) {
+                try {
+                    mToken.linkToDeath(this, 0);
+                } catch (RemoteException e) {
+                    throw new IllegalStateException("Client already dead", e);
+                }
+                mLinked = true;
+            }
+            if (mConfig == null) {
+                try {
+                    // This method uses PowerHAL directly through the SDK,
+                    // to avoid needing to pass the ChannelConfig through JNI.
+                    mConfig = mPowerHal.getSessionChannel(mTgid, mUid);
+                } catch (RemoteException e) {
+                    removeChannelItem(mTgid, mUid);
+                    throw new IllegalStateException("Failed to create session channel!", e);
+                }
+            }
+        }
+
+        ChannelConfig getConfig() {
+            return mConfig;
+        }
+
+        // To avoid accidental double-linking / unlinking
+        boolean mLinked;
+        final int mTgid;
+        final int mUid;
+        final IBinder mToken;
+        ChannelConfig mConfig;
+    }
+
     final class CleanUpHandler extends Handler {
         // status of processed tid used for caching
         private static final int TID_NOT_CHECKED = 0;
@@ -570,6 +722,18 @@ public final class HintManagerService extends SystemService {
         return mService;
     }
 
+    @VisibleForTesting
+    Boolean hasChannel(int tgid, int uid) {
+        synchronized (mChannelMapLock) {
+            TreeMap<Integer, ChannelItem> uidMap = mChannelMap.get(uid);
+            if (uidMap != null) {
+                ChannelItem item = uidMap.get(tgid);
+                return item != null;
+            }
+            return false;
+        }
+    }
+
     // returns the first invalid tid or null if not found
     private Integer checkTidValid(int uid, int tgid, int [] tids, IntArray nonIsolated) {
         // Make sure all tids belongs to the same UID (including isolated UID),
@@ -709,6 +873,28 @@ public final class HintManagerService extends SystemService {
             }
         }
 
+        @Override
+        public ChannelConfig getSessionChannel(IBinder token) {
+            if (mPowerHalVersion < 5 || !adpfUseFmqChannel()) {
+                return null;
+            }
+            java.util.Objects.requireNonNull(token);
+            final int callingTgid = Process.getThreadGroupLeader(Binder.getCallingPid());
+            final int callingUid = Binder.getCallingUid();
+            ChannelItem item = getOrCreateMappedChannelItem(callingTgid, callingUid, token);
+            return item.getConfig();
+        };
+
+        @Override
+        public void closeSessionChannel() {
+            if (mPowerHalVersion < 5 || !adpfUseFmqChannel()) {
+                return;
+            }
+            final int callingTgid = Process.getThreadGroupLeader(Binder.getCallingPid());
+            final int callingUid = Binder.getCallingUid();
+            removeChannelItem(callingTgid, callingUid);
+        };
+
         @Override
         public long getHintSessionPreferredRate() {
             return mHintSessionPreferredRate;

services/core/jni/com_android_server_hint_HintManagerService.cpp

@@ -34,11 +34,8 @@
 
 #include "jni.h"
 
-using aidl::android::hardware::power::SessionConfig;
-using aidl::android::hardware::power::SessionHint;
-using aidl::android::hardware::power::SessionMode;
-using aidl::android::hardware::power::SessionTag;
-using aidl::android::hardware::power::WorkDuration;
+namespace hal = aidl::android::hardware::power;
+
 using android::power::PowerHintSessionWrapper;
 
 namespace android {
@@ -95,10 +92,11 @@ static jlong createHintSession(JNIEnv* env, int32_t tgid, int32_t uid,
 
 static jlong createHintSessionWithConfig(JNIEnv* env, int32_t tgid, int32_t uid,
                                          std::vector<int32_t> threadIds, int64_t durationNanos,
-                                         int32_t sessionTag, SessionConfig& config) {
+                                         int32_t sessionTag, hal::SessionConfig& config) {
     auto result =
             gPowerHalController.createHintSessionWithConfig(tgid, uid, threadIds, durationNanos,
-                                                            static_cast<SessionTag>(sessionTag),
+                                                            static_cast<hal::SessionTag>(
+                                                                    sessionTag),
                                                             &config);
     if (result.isOk()) {
         jlong session_ptr = reinterpret_cast<jlong>(result.value().get());
@@ -140,12 +138,12 @@ static void updateTargetWorkDuration(int64_t session_ptr, int64_t targetDuration
 }
 
 static void reportActualWorkDuration(int64_t session_ptr,
-                                     const std::vector<WorkDuration>& actualDurations) {
+                                     const std::vector<hal::WorkDuration>& actualDurations) {
     auto appSession = reinterpret_cast<PowerHintSessionWrapper*>(session_ptr);
     appSession->reportActualWorkDuration(actualDurations);
 }
 
-static void sendHint(int64_t session_ptr, SessionHint hint) {
+static void sendHint(int64_t session_ptr, hal::SessionHint hint) {
     auto appSession = reinterpret_cast<PowerHintSessionWrapper*>(session_ptr);
     appSession->sendHint(hint);
 }
@@ -155,7 +153,7 @@ static void setThreads(int64_t session_ptr, const std::vector<int32_t>& threadId
     appSession->setThreads(threadIds);
 }
 
-static void setMode(int64_t session_ptr, SessionMode mode, bool enabled) {
+static void setMode(int64_t session_ptr, hal::SessionMode mode, bool enabled) {
     auto appSession = reinterpret_cast<PowerHintSessionWrapper*>(session_ptr);
     appSession->setMode(mode, enabled);
 }
@@ -189,7 +187,7 @@ static jlong nativeCreateHintSessionWithConfig(JNIEnv* env, jclass /* clazz */,
         return 0;
     }
     std::vector<int32_t> threadIds(tidArray.get(), tidArray.get() + tidArray.size());
-    SessionConfig config;
+    hal::SessionConfig config;
     jlong out = createHintSessionWithConfig(env, tgid, uid, std::move(threadIds), durationNanos,
                                             sessionTag, config);
     if (out <= 0) {
@@ -223,7 +221,7 @@ static void nativeReportActualWorkDuration(JNIEnv* env, jclass /* clazz */, jlon
     ScopedLongArrayRO arrayActualDurations(env, actualDurations);
     ScopedLongArrayRO arrayTimeStamps(env, timeStamps);
 
-    std::vector<WorkDuration> actualList(arrayActualDurations.size());
+    std::vector<hal::WorkDuration> actualList(arrayActualDurations.size());
     for (size_t i = 0; i < arrayActualDurations.size(); i++) {
         actualList[i].timeStampNanos = arrayTimeStamps[i];
         actualList[i].durationNanos = arrayActualDurations[i];
@@ -232,7 +230,7 @@ static void nativeReportActualWorkDuration(JNIEnv* env, jclass /* clazz */, jlon
 }
 
 static void nativeSendHint(JNIEnv* env, jclass /* clazz */, jlong session_ptr, jint hint) {
-    sendHint(session_ptr, static_cast<SessionHint>(hint));
+    sendHint(session_ptr, static_cast<hal::SessionHint>(hint));
 }
 
 static void nativeSetThreads(JNIEnv* env, jclass /* clazz */, jlong session_ptr, jintArray tids) {
@@ -244,13 +242,13 @@ static void nativeSetThreads(JNIEnv* env, jclass /* clazz */, jlong session_ptr,
 
 static void nativeSetMode(JNIEnv* env, jclass /* clazz */, jlong session_ptr, jint mode,
                           jboolean enabled) {
-    setMode(session_ptr, static_cast<SessionMode>(mode), enabled);
+    setMode(session_ptr, static_cast<hal::SessionMode>(mode), enabled);
 }
 
 static void nativeReportActualWorkDuration2(JNIEnv* env, jclass /* clazz */, jlong session_ptr,
                                             jobjectArray jWorkDurations) {
     int size = env->GetArrayLength(jWorkDurations);
-    std::vector<WorkDuration> workDurations(size);
+    std::vector<hal::WorkDuration> workDurations(size);
     for (int i = 0; i < size; i++) {
         jobject workDuration = env->GetObjectArrayElement(jWorkDurations, i);
         workDurations[i].workPeriodStartTimestampNanos =

services/tests/servicestests/src/com/android/server/power/hint/HintManagerServiceTest.java

@@ -26,12 +26,15 @@ import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.any;
 import static org.mockito.Mockito.anyBoolean;
 import static org.mockito.Mockito.anyInt;
 import static org.mockito.Mockito.anyLong;
+import static org.mockito.Mockito.clearInvocations;
+import static org.mockito.Mockito.doThrow;
 import static org.mockito.Mockito.eq;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.reset;
@@ -39,9 +42,12 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.annotation.NonNull;
 import android.app.ActivityManager;
 import android.app.ActivityManagerInternal;
 import android.content.Context;
+import android.hardware.power.ChannelConfig;
+import android.hardware.power.IPower;
 import android.hardware.power.SessionConfig;
 import android.hardware.power.SessionTag;
 import android.hardware.power.WorkDuration;
@@ -50,6 +56,7 @@ import android.os.IBinder;
 import android.os.IHintSession;
 import android.os.PerformanceHintManager;
 import android.os.Process;
+import android.os.RemoteException;
 import android.platform.test.annotations.RequiresFlagsEnabled;
 import android.platform.test.flag.junit.CheckFlagsRule;
 import android.platform.test.flag.junit.DeviceFlagsValueProvider;
@@ -130,12 +137,15 @@ public class HintManagerServiceTest {
     @Mock
     private HintManagerService.NativeWrapper mNativeWrapperMock;
     @Mock
+    private IPower mIPowerMock;
+    @Mock
     private ActivityManagerInternal mAmInternalMock;
     @Rule
     public final CheckFlagsRule mCheckFlagsRule =
             DeviceFlagsValueProvider.createCheckFlagsRule();
 
     private HintManagerService mService;
+    private ChannelConfig mConfig;
 
     private static Answer<Long> fakeCreateWithConfig(Long ptr, Long sessionId) {
         return new Answer<Long>() {
@@ -149,6 +159,9 @@ public class HintManagerServiceTest {
     @Before
     public void setUp() throws Exception {
         MockitoAnnotations.initMocks(this);
+        mConfig = new ChannelConfig();
+        mConfig.readFlagBitmask = 1;
+        mConfig.writeFlagBitmask = 2;
         when(mNativeWrapperMock.halGetHintSessionPreferredRate())
                 .thenReturn(DEFAULT_HINT_PREFERRED_RATE);
         when(mNativeWrapperMock.halCreateHintSession(eq(TGID), eq(UID), eq(SESSION_TIDS_A),
@@ -170,6 +183,8 @@ public class HintManagerServiceTest {
                 any(SessionConfig.class))).thenAnswer(fakeCreateWithConfig(SESSION_PTRS[2],
                     SESSION_IDS[2]));
 
+        when(mIPowerMock.getInterfaceVersion()).thenReturn(5);
+        when(mIPowerMock.getSessionChannel(anyInt(), anyInt())).thenReturn(mConfig);
         LocalServices.removeServiceForTest(ActivityManagerInternal.class);
         LocalServices.addService(ActivityManagerInternal.class, mAmInternalMock);
     }
@@ -252,6 +267,9 @@ public class HintManagerServiceTest {
             NativeWrapper createNativeWrapper() {
                 return mNativeWrapperMock;
             }
+            IPower createIPower() {
+                return mIPowerMock;
+            }
         });
         return mService;
     }
@@ -261,6 +279,9 @@ public class HintManagerServiceTest {
             NativeWrapper createNativeWrapper() {
                 return new NativeWrapperFake();
             }
+            IPower createIPower() {
+                return mIPowerMock;
+            }
         });
         return mService;
     }
@@ -728,6 +749,102 @@ public class HintManagerServiceTest {
         verify(mNativeWrapperMock, never()).halSetMode(anyLong(), anyInt(), anyBoolean());
     }
 
+    @Test
+    public void testGetChannel() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        // Should only call once, after caching the first call
+        ChannelConfig config = service.getBinderServiceInstance().getSessionChannel(token);
+        ChannelConfig config2 = service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(1)).getSessionChannel(eq(TGID), eq(UID));
+        assertEquals(config.readFlagBitmask, mConfig.readFlagBitmask);
+        assertEquals(config.writeFlagBitmask, mConfig.writeFlagBitmask);
+        assertEquals(config2.readFlagBitmask, mConfig.readFlagBitmask);
+        assertEquals(config2.writeFlagBitmask, mConfig.writeFlagBitmask);
+    }
+
+    @Test
+    public void testGetChannelTwice() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(1)).getSessionChannel(eq(TGID), eq(UID));
+        service.getBinderServiceInstance().closeSessionChannel();
+        verify(mIPowerMock, times(1)).closeSessionChannel(eq(TGID), eq(UID));
+
+        clearInvocations(mIPowerMock);
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(1)).getSessionChannel(eq(TGID), eq(UID));
+        service.getBinderServiceInstance().closeSessionChannel();
+        verify(mIPowerMock, times(1)).closeSessionChannel(eq(TGID), eq(UID));
+    }
+
+    @Test
+    public void testGetChannelFails() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        when(mIPowerMock.getSessionChannel(anyInt(), anyInt())).thenThrow(RemoteException.class);
+
+        assertThrows(IllegalStateException.class, () -> {
+            service.getBinderServiceInstance().getSessionChannel(token);
+        });
+    }
+
+
+    @Test
+    public void testGetChannelBadVersion() throws Exception {
+        when(mIPowerMock.getInterfaceVersion()).thenReturn(3);
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        reset(mIPowerMock);
+        when(mIPowerMock.getInterfaceVersion()).thenReturn(3);
+        when(mIPowerMock.getSessionChannel(anyInt(), anyInt())).thenReturn(mConfig);
+
+        ChannelConfig channel = service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(0)).getSessionChannel(eq(TGID), eq(UID));
+        assertNull(channel);
+    }
+
+    @Test
+    public void testCloseChannel() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+        service.getBinderServiceInstance().closeSessionChannel();
+        verify(mIPowerMock, times(1)).closeSessionChannel(eq(TGID), eq(UID));
+    }
+
+    @Test
+    public void testCloseChannelFails() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+
+        doThrow(RemoteException.class).when(mIPowerMock).closeSessionChannel(anyInt(), anyInt());
+
+        assertThrows(IllegalStateException.class, () -> {
+            service.getBinderServiceInstance().closeSessionChannel();
+        });
+    }
+
+    @Test
+    public void testDoubleClose() throws Exception {
+        HintManagerService service = createService();
+        Binder token = new Binder();
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+        service.getBinderServiceInstance().closeSessionChannel();
+        service.getBinderServiceInstance().closeSessionChannel();
+        verify(mIPowerMock, times(1)).closeSessionChannel(eq(TGID), eq(UID));
+    }
+
     // This test checks that concurrent operations from different threads on IHintService,
     // IHintSession and UidObserver will not cause data race or deadlock. Ideally we should also
     // check the output of threads' reportActualDuration performance to detect lock starvation
@@ -935,4 +1052,40 @@ public class HintManagerServiceTest {
         a.reportActualWorkDuration2(WORK_DURATIONS_FIVE);
         verify(mNativeWrapperMock, never()).halReportActualWorkDuration(anyLong(), any(), any());
     }
+
+    @Test
+    public void testChannelDiesWhenTokenDies() throws Exception {
+        HintManagerService service = createService();
+
+        class DyingToken extends Binder {
+            DeathRecipient mToNotify;
+            @Override
+            public void linkToDeath(@NonNull DeathRecipient recipient, int flags) {
+                mToNotify = recipient;
+                super.linkToDeath(recipient, flags);
+            }
+
+            public void fakeDeath() {
+                mToNotify.binderDied();
+            }
+        }
+
+        DyingToken token = new DyingToken();
+
+        service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(1)).getSessionChannel(eq(TGID), eq(UID));
+        assertTrue(service.hasChannel(TGID, UID));
+
+        token.fakeDeath();
+
+        assertFalse(service.hasChannel(TGID, UID));
+        verify(mIPowerMock, times(1)).closeSessionChannel(eq(TGID), eq(UID));
+
+        clearInvocations(mIPowerMock);
+
+        token = new DyingToken();
+        service.getBinderServiceInstance().getSessionChannel(token);
+        verify(mIPowerMock, times(1)).getSessionChannel(eq(TGID), eq(UID));
+        assertTrue(service.hasChannel(TGID, UID));
+    }
 }