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Commit 17c4a944 authored by Kensuke Miyagi's avatar Kensuke Miyagi
Browse files

Fix race condition betweeen Tuner APIs and with onReclaimResources 

- Added acquire/releaseLock() in ITunerResourceManager.aidl for Tuner
  API implementations to utilize.
- Added more lock around resource related operations that have
  race condition with releaseAll() in Tuner.java
- This fix addresses race condition when Tuner object dies as well.
- Added these calls into Tuner API implementations

Also, suppress FLAG_ONEWAY warning for onReclaimResources as it is only
called against OEM/SoC packages that are part of image that goes throug
Google certification.

Bug: 206725267
Bug: 206726459
Bug: 206723996
Test: TunerTest#testResourceReclaimedDifferentProcess() and
testResourceReclaimedDifferentThread()

Change-Id: Ic9aee1e15f53b2d4984c3b4214a392c2c4d5731e
parent f5c3a290

media/java/android/media/tv/tuner/Tuner.java

+471 −213
Original line number Diff line number Diff line
@@ -74,6 +74,7 @@ import java.util.List; 
import java.util.Map;

import java.util.Objects;

import java.util.concurrent.Executor;

import java.util.concurrent.locks.ReentrantLock;



/**

 * This class is used to interact with hardware tuners devices.
@@ -248,6 +249,7 @@ public class Tuner implements AutoCloseable { 


    private static final int FILTER_CLEANUP_THRESHOLD = 256;





    /** @hide */

    @IntDef(prefix = "DVR_TYPE_", value = {DVR_TYPE_RECORD, DVR_TYPE_PLAYBACK})

    @Retention(RetentionPolicy.SOURCE)
@@ -304,6 +306,11 @@ public class Tuner implements AutoCloseable { 
    private final Object mOnTuneEventLock = new Object();

    private final Object mScanCallbackLock = new Object();

    private final Object mOnResourceLostListenerLock = new Object();

    private final ReentrantLock mFrontendLock = new ReentrantLock();

    private final ReentrantLock mLnbLock = new ReentrantLock();

    private final ReentrantLock mFrontendCiCamLock = new ReentrantLock();

    private final ReentrantLock mDemuxLock = new ReentrantLock();

    private int mRequestedCiCamId;



    private Integer mDemuxHandle;

    private Integer mFrontendCiCamHandle;
@@ -391,7 +398,12 @@ public class Tuner implements AutoCloseable { 


    /** @hide */

    public List<Integer> getFrontendIds() {

        mFrontendLock.lock();

        try {

            return nativeGetFrontendIds();

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -426,6 +438,9 @@ public class Tuner implements AutoCloseable { 
     * @param tuner the Tuner instance to share frontend resource with.

     */

    public void shareFrontendFromTuner(@NonNull Tuner tuner) {

        acquireTRMSLock("shareFrontendFromTuner()");

        mFrontendLock.lock();

        try {

            mTunerResourceManager.shareFrontend(mClientId, tuner.mClientId);

            synchronized (mIsSharedFrontend) {

                mFrontendHandle = tuner.mFrontendHandle;
@@ -433,6 +448,10 @@ public class Tuner implements AutoCloseable { 
                mIsSharedFrontend = true;

            }

            nativeShareFrontend(mFrontend.mId);

        } finally {

            releaseTRMSLock();

            mFrontendLock.unlock();

        }

    }



    /**
@@ -498,11 +517,18 @@ public class Tuner implements AutoCloseable { 
     */

    @Override

    public void close() {

        acquireTRMSLock("close()");

        try {

            releaseAll();

            TunerUtils.throwExceptionForResult(nativeClose(), "failed to close tuner");

        } finally {

            releaseTRMSLock();

        }

    }



    private void releaseAll() {

        mFrontendLock.lock();

        try {

            if (mFrontendHandle != null) {

                synchronized (mIsSharedFrontend) {

                    if (!mIsSharedFrontend) {
@@ -520,9 +546,21 @@ public class Tuner implements AutoCloseable { 
                mFrontendHandle = null;

                mFrontend = null;

            }

        } finally {

            mFrontendLock.unlock();

        }



        mLnbLock.lock();

        try {

            if (mLnb != null) {

                mLnb.close();

            }

        } finally {

            mLnbLock.unlock();

        }



        mFrontendCiCamLock.lock();

        try {

            if (mFrontendCiCamHandle != null) {

                int result = nativeUnlinkCiCam(mFrontendCiCamId);

                if (result == RESULT_SUCCESS) {
@@ -531,6 +569,10 @@ public class Tuner implements AutoCloseable { 
                    mFrontendCiCamHandle = null;

                }

            }

        } finally {

            mFrontendCiCamLock.unlock();

        }



        synchronized (mDescramblers) {

            if (!mDescramblers.isEmpty()) {

                for (Map.Entry<Integer, WeakReference<Descrambler>> d : mDescramblers.entrySet()) {
@@ -543,6 +585,7 @@ public class Tuner implements AutoCloseable { 
                mDescramblers.clear();

            }

        }



        synchronized (mFilters) {

            if (!mFilters.isEmpty()) {

                for (WeakReference<Filter> weakFilter : mFilters) {
@@ -554,6 +597,9 @@ public class Tuner implements AutoCloseable { 
                mFilters.clear();

            }

        }



        mDemuxLock.lock();

        try {

            if (mDemuxHandle != null) {

                int res = nativeCloseDemux(mDemuxHandle);

                if (res != Tuner.RESULT_SUCCESS) {
@@ -562,6 +608,9 @@ public class Tuner implements AutoCloseable { 
                mTunerResourceManager.releaseDemux(mDemuxHandle, mClientId);

                mDemuxHandle = null;

            }

        } finally {

            mDemuxLock.unlock();

        }



        mTunerResourceManager.unregisterClientProfile(mClientId);
@@ -763,9 +812,12 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int tune(@NonNull FrontendSettings settings) {

        mFrontendLock.lock();

        try {

            final int type = settings.getType();

            if (mFrontendHandle != null && type != mFrontendType) {

            Log.e(TAG, "Frontend was opened with type " + mFrontendType + ", new type is " + type);

                Log.e(TAG, "Frontend was opened with type " + mFrontendType

                        + ", new type is " + type);

                return RESULT_INVALID_STATE;

            }

            Log.d(TAG, "Tune to " + settings.getFrequencyLong());
@@ -776,16 +828,22 @@ public class Tuner implements AutoCloseable { 
                    return RESULT_UNAVAILABLE;

                }

            }

        if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND)) {



            if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND, mFrontendLock)) {

                mFrontendInfo = null;

                Log.d(TAG, "Write Stats Log for tuning.");

                FrameworkStatsLog

                        .write(FrameworkStatsLog.TV_TUNER_STATE_CHANGED, mUserId,

                            FrameworkStatsLog.TV_TUNER_STATE_CHANGED__STATE__TUNING);

            return nativeTune(settings.getType(), settings);

        }

                int res = nativeTune(settings.getType(), settings);

                return res;

            } else {

                return RESULT_UNAVAILABLE;

            }

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**

     * Stops a previous tuning.
@@ -797,7 +855,12 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int cancelTuning() {

        mFrontendLock.lock();

        try {

            return nativeStopTune();

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -824,11 +887,15 @@ public class Tuner implements AutoCloseable { 
    @Result

    public int scan(@NonNull FrontendSettings settings, @ScanType int scanType,

            @NonNull @CallbackExecutor Executor executor, @NonNull ScanCallback scanCallback) {



        mFrontendLock.lock();

        try {

            synchronized (mScanCallbackLock) {

                // Scan can be called again for blink scan if scanCallback and executor are same as

                //before.

                if (((mScanCallback != null) && (mScanCallback != scanCallback))

                || ((mScanCallbackExecutor != null) && (mScanCallbackExecutor != executor))) {

                        || ((mScanCallbackExecutor != null)

                            && (mScanCallbackExecutor != executor))) {

                    throw new IllegalStateException(

                        "Different Scan session already in progress.  stopScan must be called "

                            + "before a new scan session can be " + "started.");
@@ -841,7 +908,8 @@ public class Tuner implements AutoCloseable { 
                        return RESULT_UNAVAILABLE;

                    }

                }

            if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND)) {

                if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND,

                          mFrontendLock)) {

                    mScanCallback = scanCallback;

                    mScanCallbackExecutor = executor;

                    mFrontendInfo = null;
@@ -852,6 +920,9 @@ public class Tuner implements AutoCloseable { 
                }

                return RESULT_UNAVAILABLE;

            }

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -867,6 +938,8 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int cancelScanning() {

        mFrontendLock.lock();

        try {

            synchronized (mScanCallbackLock) {

                FrameworkStatsLog.write(FrameworkStatsLog.TV_TUNER_STATE_CHANGED, mUserId,

                        FrameworkStatsLog.TV_TUNER_STATE_CHANGED__STATE__SCAN_STOPPED);
@@ -876,6 +949,9 @@ public class Tuner implements AutoCloseable { 
                mScanCallbackExecutor = null;

                return retVal;

            }

        } finally {

            mFrontendLock.unlock();

        }

    }



    private boolean requestFrontend() {
@@ -903,7 +979,12 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    private int setLnb(@NonNull Lnb lnb) {

        mLnbLock.lock();

        try {

            return nativeSetLnb(lnb);

        } finally {

            mLnbLock.unlock();

        }

    }



    /**
@@ -929,10 +1010,15 @@ public class Tuner implements AutoCloseable { 
     */

    @Nullable

    public FrontendStatus getFrontendStatus(@NonNull @FrontendStatusType int[] statusTypes) {

        mFrontendLock.lock();

        try {

            if (mFrontend == null) {

                throw new IllegalStateException("frontend is not initialized");

            }

            return nativeGetFrontendStatus(statusTypes);

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -942,11 +1028,16 @@ public class Tuner implements AutoCloseable { 
     * @return the id of hardware A/V sync.

     */

    public int getAvSyncHwId(@NonNull Filter filter) {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return INVALID_AV_SYNC_ID;

            }

            Integer id = nativeGetAvSyncHwId(filter);

            return id == null ? INVALID_AV_SYNC_ID : id;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -959,11 +1050,16 @@ public class Tuner implements AutoCloseable { 
     * @return the current timestamp of hardware A/V sync.

     */

    public long getAvSyncTime(int avSyncHwId) {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return INVALID_TIMESTAMP;

            }

            Long time = nativeGetAvSyncTime(avSyncHwId);

            return time == null ? INVALID_TIMESTAMP : time;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -980,10 +1076,15 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int connectCiCam(int ciCamId) {

        if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return nativeConnectCiCam(ciCamId);

            }

            return RESULT_UNAVAILABLE;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1011,14 +1112,30 @@ public class Tuner implements AutoCloseable { 
     *         {@link TunerVersionChecker#getTunerVersion()}.

     */

    public int connectFrontendToCiCam(int ciCamId) {

        if (TunerVersionChecker.checkHigherOrEqualVersionTo(TunerVersionChecker.TUNER_VERSION_1_1,

        // TODO: change this so TRMS lock is held only when the resource handles for

        // CiCam/Frontend is null. Current implementation can only handle one local lock for that.

        acquireTRMSLock("connectFrontendToCiCam()");

        mFrontendCiCamLock.lock();

        mFrontendLock.lock();

        try {

            if (TunerVersionChecker.checkHigherOrEqualVersionTo(

                    TunerVersionChecker.TUNER_VERSION_1_1,

                    "linkFrontendToCiCam")) {

            if (checkCiCamResource(ciCamId)

                    && checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND)) {

                mRequestedCiCamId = ciCamId;

                // No need to unlock mFrontendCiCamLock and mFrontendLock below becauase

                // TRMS lock is already acquired. Pass null to disable lock related operations

                if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND_CICAM, null)

                        && checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND, null)

                    ) {

                    return nativeLinkCiCam(ciCamId);

                }

            }

            return INVALID_LTS_ID;

        } finally {

            releaseTRMSLock();

            mFrontendCiCamLock.unlock();

            mFrontendLock.unlock();

        }

    }



    /**
@@ -1033,10 +1150,15 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int disconnectCiCam() {

        mDemuxLock.lock();

        try {

            if (mDemuxHandle != null) {

                return nativeDisconnectCiCam();

            }

            return RESULT_UNAVAILABLE;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1057,8 +1179,12 @@ public class Tuner implements AutoCloseable { 
     */

    @Result

    public int disconnectFrontendToCiCam(int ciCamId) {

        if (TunerVersionChecker.checkHigherOrEqualVersionTo(TunerVersionChecker.TUNER_VERSION_1_1,

        acquireTRMSLock("disconnectFrontendToCiCam()");

        try {

            if (TunerVersionChecker.checkHigherOrEqualVersionTo(

                    TunerVersionChecker.TUNER_VERSION_1_1,

                    "unlinkFrontendToCiCam")) {

                mFrontendCiCamLock.lock();

                if (mFrontendCiCamHandle != null && mFrontendCiCamId != null

                        && mFrontendCiCamId == ciCamId) {

                    int result = nativeUnlinkCiCam(ciCamId);
@@ -1071,6 +1197,12 @@ public class Tuner implements AutoCloseable { 
                }

            }

            return RESULT_UNAVAILABLE;

        } finally {

            if (mFrontendCiCamLock.isLocked()) {

                mFrontendCiCamLock.unlock();

            }

            releaseTRMSLock();

        }

    }



    /**
@@ -1082,7 +1214,9 @@ public class Tuner implements AutoCloseable { 
     */

    @Nullable

    public FrontendInfo getFrontendInfo() {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND)) {

        mFrontendLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND, mFrontendLock)) {

                return null;

            }

            if (mFrontend == null) {
@@ -1092,6 +1226,9 @@ public class Tuner implements AutoCloseable { 
                mFrontendInfo = getFrontendInfoById(mFrontend.mId);

            }

            return mFrontendInfo;

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -1114,7 +1251,12 @@ public class Tuner implements AutoCloseable { 


    /** @hide */

    public FrontendInfo getFrontendInfoById(int id) {

        mFrontendLock.lock();

        try {

            return nativeGetFrontendInfo(id);

        } finally {

            mFrontendLock.unlock();

        }

    }



    /**
@@ -1125,7 +1267,12 @@ public class Tuner implements AutoCloseable { 
     */

    @Nullable

    public DemuxCapabilities getDemuxCapabilities() {

        mDemuxLock.lock();

        try {

            return nativeGetDemuxCapabilities();

        } finally {

            mDemuxLock.unlock();

        }

    }



    private void onFrontendEvent(int eventType) {
@@ -1417,7 +1564,9 @@ public class Tuner implements AutoCloseable { 
    public Filter openFilter(@Type int mainType, @Subtype int subType,

            @BytesLong long bufferSize, @CallbackExecutor @Nullable Executor executor,

            @Nullable FilterCallback cb) {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return null;

            }

            Filter filter = nativeOpenFilter(
@@ -1443,6 +1592,9 @@ public class Tuner implements AutoCloseable { 
                }

            }

            return filter;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1457,18 +1609,24 @@ public class Tuner implements AutoCloseable { 
     */

    @Nullable

    public Lnb openLnb(@CallbackExecutor @NonNull Executor executor, @NonNull LnbCallback cb) {

        mLnbLock.lock();

        try {

            Objects.requireNonNull(executor, "executor must not be null");

            Objects.requireNonNull(cb, "LnbCallback must not be null");

            if (mLnb != null) {

                mLnb.setCallback(executor, cb, this);

                return mLnb;

            }

        if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_LNB) && mLnb != null) {

            if (checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_LNB, mLnbLock)

                    && mLnb != null) {

                mLnb.setCallback(executor, cb, this);

                setLnb(mLnb);

                return mLnb;

            }

            return null;

        } finally {

            mLnbLock.unlock();

        }

    }



    /**
@@ -1483,6 +1641,8 @@ public class Tuner implements AutoCloseable { 
    @Nullable

    public Lnb openLnbByName(@NonNull String name, @CallbackExecutor @NonNull Executor executor,

            @NonNull LnbCallback cb) {

        mLnbLock.lock();

        try {

            Objects.requireNonNull(name, "LNB name must not be null");

            Objects.requireNonNull(executor, "executor must not be null");

            Objects.requireNonNull(cb, "LnbCallback must not be null");
@@ -1497,6 +1657,9 @@ public class Tuner implements AutoCloseable { 
                setLnb(mLnb);

            }

            return mLnb;

        } finally {

            mLnbLock.unlock();

        }

    }



    private boolean requestLnb() {
@@ -1518,10 +1681,15 @@ public class Tuner implements AutoCloseable { 
     */

    @Nullable

    public TimeFilter openTimeFilter() {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return null;

            }

            return nativeOpenTimeFilter();

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1532,10 +1700,15 @@ public class Tuner implements AutoCloseable { 
    @RequiresPermission(android.Manifest.permission.ACCESS_TV_DESCRAMBLER)

    @Nullable

    public Descrambler openDescrambler() {

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

        mDemuxLock.lock();

        try {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return null;

            }

            return requestDescrambler();

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1553,14 +1726,19 @@ public class Tuner implements AutoCloseable { 
            @BytesLong long bufferSize,

            @CallbackExecutor @NonNull Executor executor,

            @NonNull OnRecordStatusChangedListener l) {

        mDemuxLock.lock();

        try {

            Objects.requireNonNull(executor, "executor must not be null");

            Objects.requireNonNull(l, "OnRecordStatusChangedListener must not be null");

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return null;

            }

            DvrRecorder dvr = nativeOpenDvrRecorder(bufferSize);

            dvr.setListener(executor, l);

            return dvr;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1578,14 +1756,19 @@ public class Tuner implements AutoCloseable { 
            @BytesLong long bufferSize,

            @CallbackExecutor @NonNull Executor executor,

            @NonNull OnPlaybackStatusChangedListener l) {

        mDemuxLock.lock();

        try {

            Objects.requireNonNull(executor, "executor must not be null");

            Objects.requireNonNull(l, "OnPlaybackStatusChangedListener must not be null");

        if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX)) {

            if (!checkResource(TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX, mDemuxLock)) {

                return null;

            }

            DvrPlayback dvr = nativeOpenDvrPlayback(bufferSize);

            dvr.setListener(executor, l);

            return dvr;

        } finally {

            mDemuxLock.unlock();

        }

    }



    /**
@@ -1602,6 +1785,8 @@ public class Tuner implements AutoCloseable { 
    static public SharedFilter openSharedFilter(@NonNull Context context,

            @NonNull String sharedFilterToken, @CallbackExecutor @NonNull Executor executor,

            @NonNull SharedFilterCallback cb) {

        // TODO: check what happenes when onReclaimResources() is called and see if

        // this needs to be protected with TRMS lock

        Objects.requireNonNull(sharedFilterToken, "sharedFilterToken must not be null");

        Objects.requireNonNull(executor, "executor must not be null");

        Objects.requireNonNull(cb, "SharedFilterCallback must not be null");
@@ -1665,22 +1850,28 @@ public class Tuner implements AutoCloseable { 
        return granted;

    }



    private boolean checkResource(int resourceType)  {

    private boolean checkResource(int resourceType, ReentrantLock localLock)  {

        switch (resourceType) {

            case TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND: {

                if (mFrontendHandle == null && !requestFrontend()) {

                if (mFrontendHandle == null && !requestResource(resourceType, localLock)) {

                    return false;

                }

                break;

            }

            case TunerResourceManager.TUNER_RESOURCE_TYPE_LNB: {

                if (mLnb == null && !requestLnb()) {

                if (mLnb == null && !requestResource(resourceType, localLock)) {

                    return false;

                }

                break;

            }

            case TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX: {

                if (mDemuxHandle == null && !requestDemux()) {

                if (mDemuxHandle == null && !requestResource(resourceType, localLock)) {

                    return false;

                }

                break;

            }

            case TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND_CICAM: {

                if (mFrontendCiCamHandle == null && !requestResource(resourceType, localLock)) {

                    return false;

                }

                break;
@@ -1691,24 +1882,91 @@ public class Tuner implements AutoCloseable { 
        return true;

    }



    private boolean checkCiCamResource(int ciCamId) {

        if (mFrontendCiCamHandle == null && !requestFrontendCiCam(ciCamId)) {

    // Expected flow of how to use this function is:

    // 1) lock the localLock and check if the resource is already held

    // 2) if yes, no need to call this function and continue with the handle with the lock held

    // 3) if no, then first release the held lock and grab the TRMS lock to avoid deadlock

    // 4) grab the local lock again and release the TRMS lock

    // If localLock is null, we'll assume the caller does not want the lock related operations

    private boolean requestResource(int resourceType, ReentrantLock localLock)  {

        boolean enableLockOperations = localLock != null;



        // release the local lock first to avoid deadlock

        if (enableLockOperations) {

            if (localLock.isLocked()) {

                localLock.unlock();

            } else {

                throw new IllegalStateException("local lock must be locked beforehand");

            }

        }



        // now safe to grab TRMS lock

        if (enableLockOperations) {

            acquireTRMSLock("requestResource:" + resourceType);

        }



        try {

            // lock the local lock

            if (enableLockOperations) {

                localLock.lock();

            }

            switch (resourceType) {

                case TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND: {

                    return requestFrontend();

                }

                case TunerResourceManager.TUNER_RESOURCE_TYPE_LNB: {

                    return requestLnb();

                }

                case TunerResourceManager.TUNER_RESOURCE_TYPE_DEMUX: {

                    return requestDemux();

                }

                case TunerResourceManager.TUNER_RESOURCE_TYPE_FRONTEND_CICAM: {

                    return requestFrontendCiCam(mRequestedCiCamId);

                }

                default:

                    return false;

            }

        return true;

        } finally {

            if (enableLockOperations) {

                releaseTRMSLock();

            }

        }

    }



    /* package */ void releaseLnb() {

        acquireTRMSLock("releaseLnb()");

        mLnbLock.lock();

        try {

            if (mLnbHandle != null) {

                // LNB handle can be null if it's opened by name.

                mTunerResourceManager.releaseLnb(mLnbHandle, mClientId);

                mLnbHandle = null;

            }

            mLnb = null;

        } finally {

            releaseTRMSLock();

            mLnbLock.unlock();

        }

    }



    /** @hide */

    public int getClientId() {

        return mClientId;

    }



    private void acquireTRMSLock(String functionNameForLog) {

        if (DEBUG) {

            Log.d(TAG, "ATTEMPT:acquireLock() in " + functionNameForLog

                    + "for clientId:" + mClientId);

        }

        if (!mTunerResourceManager.acquireLock(mClientId)) {

            Log.e(TAG, "FAILED:acquireLock() in " + functionNameForLog

                    + " for clientId:" + mClientId + " - this can cause deadlock between"

                    + " Tuner API calls and onReclaimResources()");

        }

    }



    private void releaseTRMSLock() {

        mTunerResourceManager.releaseLock(mClientId);

    }

}

media/java/android/media/tv/tunerresourcemanager/TunerResourceManager.java

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media/java/android/media/tv/tunerresourcemanager/aidl/android/media/tv/tunerresourcemanager/ITunerResourceManager.aidl

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services/core/java/com/android/server/tv/tunerresourcemanager/TunerResourceManagerService.java

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