hardware/camera/CallbackWorkerThread.cpp - LeafOS-Devices/android_device_samsung_universal7904-common - Gitiles

 /*
  * Copyright (C) 2019, The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /*
  * Camera HAL "CallbackWorkerThread" workaround description
  *
  * The camera HAL of the Exynos7580 (A3, A5, ... 2016) reguralry deadlocks when using
  * most camera apps, this happens a lot when using Google Camera but does occur
  * occasionally in Snap.
  *
  * The issue was tracked down to the way that Samsung operates their HAL, all operations
  * are run in multiple threads and the different callbacks are executed from one of these
  * threads.
  *
  * The deadlocks occur when the camera client executes a function like cancel_auto_focus
  * or stop_preview and a callback from the HAL occurs at around the same time. The HAL
  * waits for the callback functions to return before they finish processing the client
  * calls and the client stops processing callbacks until their calling function completes.
  *
  * You end up in a state when both the HAL and the client are waiting for the other
  * process to finish and so end up with a deadlock of the HAL/Client which only a reboot
  * can cure.
  *
  * This worker thread offloads the actual callbacks to another thread which allows the
  * HAL to finish the client calls and avoid the deadlock scenario.
  *
  */

 #define LOG_NDEBUG 1
 #define LOG_TAG "Camera2WrapperCbThread"

 #include "CallbackWorkerThread.h"
 #include <iostream>
 #include <cutils/log.h>

 using namespace std;

 #define MSG_EXIT_THREAD         1
 #define MSG_EXECUTE_CALLBACK      2
 #define MSG_UPDATE_CALLBACKS    3

 struct ThreadMsg
 {
     ThreadMsg(int i, const void* m, long long ts) { id = i; msg = m; CallerTS = ts; }
     int id;
     const void* msg;
     long long CallerTS;
 };

 CallbackWorkerThread::CallbackWorkerThread() : m_thread(0) {
 }

 CallbackWorkerThread::~CallbackWorkerThread() {
     ExitThread();
 }

 bool CallbackWorkerThread::CreateThread() {
     if (!m_thread)
         m_thread = new thread(&CallbackWorkerThread::Process, this);
     return true;
 }

 void CallbackWorkerThread::ExitThread() {
     if (!m_thread)
         return;

     /* Create the exit thread worker message */
     ThreadMsg* threadMsg = new ThreadMsg(MSG_EXIT_THREAD, 0, GetTimestamp());

     /* Add it to the message queue */
     {
         lock_guard<mutex> lock(m_mutex);
         m_queue.push(threadMsg);
         m_cv.notify_one();
     }

     /* Join the thread and then cleanup */
     m_thread->join();
     delete m_thread;
     m_thread = 0;
 }

 void CallbackWorkerThread::AddCallback(const WorkerMessage* data) {
     /* Assert that the thread exists */
     ALOG_ASSERT(m_thread != NULL);

     /* Create a new worker thread message from the data */
     ThreadMsg* threadMsg = new ThreadMsg(MSG_EXECUTE_CALLBACK, data, GetTimestamp());

     /* Add it to our worker queue and notify the worker */
     std::unique_lock<std::mutex> lk(m_mutex);
     m_queue.push(threadMsg);
     m_cv.notify_one();
 }

 void CallbackWorkerThread::SetCallbacks(const CallbackData* data) {
     /* Assert that the thread exists */
     ALOG_ASSERT(m_thread != NULL);

     /* Create a new worker thread message from the callback data */
     ThreadMsg* threadMsg = new ThreadMsg(MSG_UPDATE_CALLBACKS, data, GetTimestamp());

     /* Add it to our worker queue and notify the worker */
     std::unique_lock<std::mutex> lk(m_mutex);
     m_queue.push(threadMsg);
     m_cv.notify_one();
 }

 void CallbackWorkerThread::ClearCallbacks() {
     /* Assert that the thread exists */
     ALOG_ASSERT(m_thread != NULL);

     /* Lock the mutex and clear the message queue */
     std::unique_lock<std::mutex> lk(m_mutex);

     ALOGV("%s: Clearing %zu messages", __FUNCTION__, m_queue.size());

     /* Whilst the queue is not empty */
     while (!m_queue.empty()) {
         /* Pop the message from the queue and delete the allocated data */
         ThreadMsg* msg = m_queue.front();
         m_queue.pop();
         delete msg;
     }

     m_cv.notify_one();
 }

 void CallbackWorkerThread::Process() {
     camera_notify_callback UserNotifyCb = NULL;
     camera_data_callback UserDataCb = NULL;

     while (1) {
         ThreadMsg* msg = 0;
         {
             /* Wait for a message to be added to the queue */
             std::unique_lock<std::mutex> lk(m_mutex);
             while (m_queue.empty())
                 m_cv.wait(lk);

             if (m_queue.empty())
                 continue;

             msg = m_queue.front();
             m_queue.pop();
         }

         switch (msg->id) {
             case MSG_EXECUTE_CALLBACK:
             {
                 /* Assert that we have a valid message */
                 ALOG_ASSERT(msg->msg != NULL);

                 /* Cast the the ThreadMsg void* data back to a WorkerMessage* */
                 const WorkerMessage* userData = static_cast<const WorkerMessage*>(msg->msg);

                 /* If the callback is not stale (newer than 5mS) */
                 if(GetTimestamp() - msg->CallerTS < 5) {
                     /* If the callback type is set to notifycb */
                     if(userData->CbType == CB_TYPE_NOTIFY) {
                         /* Execute the users notify callback if it is valid */
                         if(UserNotifyCb != NULL) {
                             ALOGV("%s: UserNotifyCb: %i %i %i %p", __FUNCTION__, userData->msg_type, userData->ext1, userData->ext2, userData->user);
                             UserNotifyCb(userData->msg_type, userData->ext1, userData->ext2, userData->user);
                         }
                     } /* If the callback type is set to notifycb */
                     else if(userData->CbType == CB_TYPE_DATA) {
                         /* Execute the users data callback if it is valid */
                         if(UserDataCb != NULL) {
                             ALOGV("%s: UserDataCb: %i %p %i %p %p", __FUNCTION__, userData->msg_type, userData->data, userData->index, userData->metadata, userData->user);
                             UserDataCb(userData->msg_type, userData->data, userData->index, userData->metadata, userData->user);
                         }
                     }
                 } else {
                     /* If the callback type is set to notifycb */
                     if(userData->CbType == CB_TYPE_NOTIFY) {
                             ALOGV("%s: UserNotifyCb Stale: %llimS old", __FUNCTION__, GetTimestamp() - msg->CallerTS);
                     } /* If the callback type is set to notifycb */
                     else if(userData->CbType == CB_TYPE_DATA) {
                             ALOGV("%s: UserDataCb Stale: %llimS old", __FUNCTION__, GetTimestamp() - msg->CallerTS);
                     }
                 }

                 /* Cleanup allocated data */
                 delete userData;
                 delete msg;
                 break;
             }

             case MSG_UPDATE_CALLBACKS:
             {
                 /* Assert that we have a valid message */
                 ALOG_ASSERT(msg->msg != NULL);

                 /* Cast the the ThreadMsg void* data back to a CallbackData* */
                 const CallbackData* callbackData = static_cast<const CallbackData*>(msg->msg);

                 ALOGV("%s: UpdateCallbacks", __FUNCTION__);

                 /* Copy the new callback pointers */
                 UserNotifyCb = callbackData->NewUserNotifyCb;
                 UserDataCb = callbackData->NewUserDataCb;

                 /* Cleanup allocated data */
                 delete callbackData;
                 delete msg;
                 break;
             }

             case MSG_EXIT_THREAD:
             {
                 /* Delete current message */
                 delete msg;
                 /* Then delete all pending messages in the queue */
                 std::unique_lock<std::mutex> lk(m_mutex);
                 /* Whilst the queue is not empty */
                 while (!m_queue.empty()) {
                     /* Pop the message from the queue and delete the allocated data */
                     msg = m_queue.front();
                     m_queue.pop();
                     delete msg;
                 }

                 ALOGV("%s: Exit Thread", __FUNCTION__);
                 return;
             }

             default:
                 /* Error if we get here */
 	            ALOG_ASSERT(0);
         }
     }
 }


 /* based on current_timestamp() function from stack overflow:
  * https://stackoverflow.com/questions/3756323/how-to-get-the-current-time-in-milliseconds-from-c-in-linux/17083824
  */

 long long CallbackWorkerThread::GetTimestamp() {
     struct timeval te;
     gettimeofday(&te, NULL); // get current time
     long long milliseconds = te.tv_sec*1000LL + te.tv_usec/1000; // calculate milliseconds
     return milliseconds;
 }
	/*
	* Copyright (C) 2019, The LineageOS Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/*
	* Camera HAL "CallbackWorkerThread" workaround description
	*
	* The camera HAL of the Exynos7580 (A3, A5, ... 2016) reguralry deadlocks when using
	* most camera apps, this happens a lot when using Google Camera but does occur
	* occasionally in Snap.
	*
	* The issue was tracked down to the way that Samsung operates their HAL, all operations
	* are run in multiple threads and the different callbacks are executed from one of these
	* threads.
	*
	* The deadlocks occur when the camera client executes a function like cancel_auto_focus
	* or stop_preview and a callback from the HAL occurs at around the same time. The HAL
	* waits for the callback functions to return before they finish processing the client
	* calls and the client stops processing callbacks until their calling function completes.
	*
	* You end up in a state when both the HAL and the client are waiting for the other
	* process to finish and so end up with a deadlock of the HAL/Client which only a reboot
	* can cure.
	*
	* This worker thread offloads the actual callbacks to another thread which allows the
	* HAL to finish the client calls and avoid the deadlock scenario.
	*
	*/

	#define LOG_NDEBUG 1
	#define LOG_TAG "Camera2WrapperCbThread"

	#include "CallbackWorkerThread.h"
	#include <iostream>
	#include <cutils/log.h>

	using namespace std;

	#define MSG_EXIT_THREAD 1
	#define MSG_EXECUTE_CALLBACK 2
	#define MSG_UPDATE_CALLBACKS 3

	struct ThreadMsg
	{
	ThreadMsg(int i, const void* m, long long ts) { id = i; msg = m; CallerTS = ts; }
	int id;
	const void* msg;
	long long CallerTS;
	};

	CallbackWorkerThread::CallbackWorkerThread() : m_thread(0) {
	}

	CallbackWorkerThread::~CallbackWorkerThread() {
	ExitThread();
	}

	bool CallbackWorkerThread::CreateThread() {
	if (!m_thread)
	m_thread = new thread(&CallbackWorkerThread::Process, this);
	return true;
	}

	void CallbackWorkerThread::ExitThread() {
	if (!m_thread)
	return;

	/* Create the exit thread worker message */
	ThreadMsg* threadMsg = new ThreadMsg(MSG_EXIT_THREAD, 0, GetTimestamp());

	/* Add it to the message queue */
	{
	lock_guard<mutex> lock(m_mutex);
	m_queue.push(threadMsg);
	m_cv.notify_one();
	}

	/* Join the thread and then cleanup */
	m_thread->join();
	delete m_thread;
	m_thread = 0;
	}

	void CallbackWorkerThread::AddCallback(const WorkerMessage* data) {
	/* Assert that the thread exists */
	ALOG_ASSERT(m_thread != NULL);

	/* Create a new worker thread message from the data */
	ThreadMsg* threadMsg = new ThreadMsg(MSG_EXECUTE_CALLBACK, data, GetTimestamp());

	/* Add it to our worker queue and notify the worker */
	std::unique_lock<std::mutex> lk(m_mutex);
	m_queue.push(threadMsg);
	m_cv.notify_one();
	}

	void CallbackWorkerThread::SetCallbacks(const CallbackData* data) {
	/* Assert that the thread exists */
	ALOG_ASSERT(m_thread != NULL);

	/* Create a new worker thread message from the callback data */
	ThreadMsg* threadMsg = new ThreadMsg(MSG_UPDATE_CALLBACKS, data, GetTimestamp());

	/* Add it to our worker queue and notify the worker */
	std::unique_lock<std::mutex> lk(m_mutex);
	m_queue.push(threadMsg);
	m_cv.notify_one();
	}

	void CallbackWorkerThread::ClearCallbacks() {
	/* Assert that the thread exists */
	ALOG_ASSERT(m_thread != NULL);

	/* Lock the mutex and clear the message queue */
	std::unique_lock<std::mutex> lk(m_mutex);

	ALOGV("%s: Clearing %zu messages", __FUNCTION__, m_queue.size());

	/* Whilst the queue is not empty */
	while (!m_queue.empty()) {
	/* Pop the message from the queue and delete the allocated data */
	ThreadMsg* msg = m_queue.front();
	m_queue.pop();
	delete msg;
	}

	m_cv.notify_one();
	}

	void CallbackWorkerThread::Process() {
	camera_notify_callback UserNotifyCb = NULL;
	camera_data_callback UserDataCb = NULL;

	while (1) {
	ThreadMsg* msg = 0;
	{
	/* Wait for a message to be added to the queue */
	std::unique_lock<std::mutex> lk(m_mutex);
	while (m_queue.empty())
	m_cv.wait(lk);

	if (m_queue.empty())
	continue;

	msg = m_queue.front();
	m_queue.pop();
	}

	switch (msg->id) {
	case MSG_EXECUTE_CALLBACK:
	{
	/* Assert that we have a valid message */
	ALOG_ASSERT(msg->msg != NULL);

	/* Cast the the ThreadMsg void* data back to a WorkerMessage* */
	const WorkerMessage* userData = static_cast<const WorkerMessage*>(msg->msg);

	/* If the callback is not stale (newer than 5mS) */
	if(GetTimestamp() - msg->CallerTS < 5) {
	/* If the callback type is set to notifycb */
	if(userData->CbType == CB_TYPE_NOTIFY) {
	/* Execute the users notify callback if it is valid */
	if(UserNotifyCb != NULL) {
	ALOGV("%s: UserNotifyCb: %i %i %i %p", __FUNCTION__, userData->msg_type, userData->ext1, userData->ext2, userData->user);
	UserNotifyCb(userData->msg_type, userData->ext1, userData->ext2, userData->user);
	}
	} /* If the callback type is set to notifycb */
	else if(userData->CbType == CB_TYPE_DATA) {
	/* Execute the users data callback if it is valid */
	if(UserDataCb != NULL) {
	ALOGV("%s: UserDataCb: %i %p %i %p %p", __FUNCTION__, userData->msg_type, userData->data, userData->index, userData->metadata, userData->user);
	UserDataCb(userData->msg_type, userData->data, userData->index, userData->metadata, userData->user);
	}
	}
	} else {
	/* If the callback type is set to notifycb */
	if(userData->CbType == CB_TYPE_NOTIFY) {
	ALOGV("%s: UserNotifyCb Stale: %llimS old", __FUNCTION__, GetTimestamp() - msg->CallerTS);
	} /* If the callback type is set to notifycb */
	else if(userData->CbType == CB_TYPE_DATA) {
	ALOGV("%s: UserDataCb Stale: %llimS old", __FUNCTION__, GetTimestamp() - msg->CallerTS);
	}
	}

	/* Cleanup allocated data */
	delete userData;
	delete msg;
	break;
	}

	case MSG_UPDATE_CALLBACKS:
	{
	/* Assert that we have a valid message */
	ALOG_ASSERT(msg->msg != NULL);

	/* Cast the the ThreadMsg void* data back to a CallbackData* */
	const CallbackData* callbackData = static_cast<const CallbackData*>(msg->msg);

	ALOGV("%s: UpdateCallbacks", __FUNCTION__);

	/* Copy the new callback pointers */
	UserNotifyCb = callbackData->NewUserNotifyCb;
	UserDataCb = callbackData->NewUserDataCb;

	/* Cleanup allocated data */
	delete callbackData;
	delete msg;
	break;
	}

	case MSG_EXIT_THREAD:
	{
	/* Delete current message */
	delete msg;
	/* Then delete all pending messages in the queue */
	std::unique_lock<std::mutex> lk(m_mutex);
	/* Whilst the queue is not empty */
	while (!m_queue.empty()) {
	/* Pop the message from the queue and delete the allocated data */
	msg = m_queue.front();
	m_queue.pop();
	delete msg;
	}

	ALOGV("%s: Exit Thread", __FUNCTION__);
	return;
	}

	default:
	/* Error if we get here */
	ALOG_ASSERT(0);
	}
	}
	}


	/* based on current_timestamp() function from stack overflow:
	* https://stackoverflow.com/questions/3756323/how-to-get-the-current-time-in-milliseconds-from-c-in-linux/17083824
	*/

	long long CallbackWorkerThread::GetTimestamp() {
	struct timeval te;
	gettimeofday(&te, NULL); // get current time
	long long milliseconds = te.tv_sec*1000LL + te.tv_usec/1000; // calculate milliseconds
	return milliseconds;
	}