1 /*
2 * Copyright 2022 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "VsyncThread.h"
18
19 #include <utils/ThreadDefs.h>
20
21 #include <thread>
22
23 #include "Time.h"
24
25 namespace aidl::android::hardware::graphics::composer3::impl {
26 namespace {
27
28 // Returns the timepoint of the next vsync after the 'now' timepoint that is
29 // a multiple of 'vsyncPeriod' in-phase/offset-from 'previousSync'.
30 //
31 // Some examples:
32 // * vsyncPeriod=50ns previousVsync=500ns now=510ns => 550ns
33 // * vsyncPeriod=50ns previousVsync=300ns now=510ns => 550ns
34 // * vsyncPeriod=50ns previousVsync=500ns now=550ns => 550ns
GetNextVsyncInPhase(Nanoseconds vsyncPeriod,TimePoint previousVsync,TimePoint now)35 TimePoint GetNextVsyncInPhase(Nanoseconds vsyncPeriod, TimePoint previousVsync,
36 TimePoint now) {
37 const auto elapsed = Nanoseconds(now - previousVsync);
38 const auto nextMultiple = (elapsed / vsyncPeriod) + 1;
39 return previousVsync + (nextMultiple * vsyncPeriod);
40 }
41
42 } // namespace
43
VsyncThread(int64_t displayId)44 VsyncThread::VsyncThread(int64_t displayId) : mDisplayId(displayId) {
45 mPreviousVsync = std::chrono::steady_clock::now() - mVsyncPeriod;
46 }
47
~VsyncThread()48 VsyncThread::~VsyncThread() { stop(); }
49
start(int32_t vsyncPeriodNanos)50 HWC3::Error VsyncThread::start(int32_t vsyncPeriodNanos) {
51 DEBUG_LOG("%s for display:%" PRIu64, __FUNCTION__, mDisplayId);
52
53 mVsyncPeriod = Nanoseconds(vsyncPeriodNanos);
54
55 mThread = std::thread([this]() { threadLoop(); });
56
57 const std::string name =
58 "display_" + std::to_string(mDisplayId) + "_vsync_thread";
59
60 int ret = pthread_setname_np(mThread.native_handle(), name.c_str());
61 if (ret != 0) {
62 ALOGE("%s: failed to set Vsync thread name: %s", __FUNCTION__,
63 strerror(ret));
64 }
65
66 struct sched_param param = {
67 .sched_priority = ANDROID_PRIORITY_DISPLAY,
68 };
69 ret = pthread_setschedparam(mThread.native_handle(), SCHED_FIFO, ¶m);
70 if (ret != 0) {
71 ALOGE("%s: failed to set Vsync thread priority: %s", __FUNCTION__,
72 strerror(ret));
73 }
74
75 return HWC3::Error::None;
76 }
77
stop()78 HWC3::Error VsyncThread::stop() {
79 mShuttingDown.store(true);
80 mThread.join();
81
82 return HWC3::Error::None;
83 }
84
setCallbacks(const std::shared_ptr<IComposerCallback> & callback)85 HWC3::Error VsyncThread::setCallbacks(
86 const std::shared_ptr<IComposerCallback>& callback) {
87 DEBUG_LOG("%s for display:%" PRIu64, __FUNCTION__, mDisplayId);
88
89 std::unique_lock<std::mutex> lock(mStateMutex);
90
91 mCallbacks = callback;
92
93 return HWC3::Error::None;
94 }
95
setVsyncEnabled(bool enabled)96 HWC3::Error VsyncThread::setVsyncEnabled(bool enabled) {
97 DEBUG_LOG("%s for display:%" PRIu64 " enabled:%d", __FUNCTION__, mDisplayId,
98 enabled);
99
100 std::unique_lock<std::mutex> lock(mStateMutex);
101
102 mVsyncEnabled = enabled;
103
104 return HWC3::Error::None;
105 }
106
scheduleVsyncUpdate(int32_t newVsyncPeriod,const VsyncPeriodChangeConstraints & constraints,VsyncPeriodChangeTimeline * outTimeline)107 HWC3::Error VsyncThread::scheduleVsyncUpdate(
108 int32_t newVsyncPeriod, const VsyncPeriodChangeConstraints& constraints,
109 VsyncPeriodChangeTimeline* outTimeline) {
110 DEBUG_LOG("%s for display:%" PRIu64, __FUNCTION__, mDisplayId);
111
112 PendingUpdate update;
113 update.period = Nanoseconds(newVsyncPeriod);
114 update.updateAfter = asTimePoint(constraints.desiredTimeNanos);
115
116 std::unique_lock<std::mutex> lock(mStateMutex);
117 mPendingUpdate.emplace(std::move(update));
118
119 TimePoint nextVsync =
120 GetNextVsyncInPhase(mVsyncPeriod, mPreviousVsync, update.updateAfter);
121
122 outTimeline->newVsyncAppliedTimeNanos = asNanosTimePoint(nextVsync);
123 outTimeline->refreshRequired = false;
124 outTimeline->refreshTimeNanos = 0;
125
126 return HWC3::Error::None;
127 }
128
updateVsyncPeriodLocked(TimePoint now)129 Nanoseconds VsyncThread::updateVsyncPeriodLocked(TimePoint now) {
130 if (mPendingUpdate && now > mPendingUpdate->updateAfter) {
131 mVsyncPeriod = mPendingUpdate->period;
132 mPendingUpdate.reset();
133 }
134
135 return mVsyncPeriod;
136 }
137
threadLoop()138 void VsyncThread::threadLoop() {
139 ALOGI("Vsync thread for display:%" PRId64 " starting", mDisplayId);
140
141 Nanoseconds vsyncPeriod = mVsyncPeriod;
142
143 int vsyncs = 0;
144 TimePoint previousLog = std::chrono::steady_clock::now();
145
146 while (!mShuttingDown.load()) {
147 TimePoint now = std::chrono::steady_clock::now();
148 TimePoint nextVsync = GetNextVsyncInPhase(vsyncPeriod, mPreviousVsync, now);
149
150 std::this_thread::sleep_until(nextVsync);
151 {
152 std::unique_lock<std::mutex> lock(mStateMutex);
153
154 mPreviousVsync = nextVsync;
155
156 // Display has finished refreshing at previous vsync period. Update the
157 // vsync period if there was a pending update.
158 vsyncPeriod = updateVsyncPeriodLocked(mPreviousVsync);
159 }
160
161 if (mVsyncEnabled) {
162 if (mCallbacks) {
163 DEBUG_LOG("%s: for display:%" PRIu64 " calling vsync", __FUNCTION__,
164 mDisplayId);
165 mCallbacks->onVsync(mDisplayId, asNanosTimePoint(nextVsync),
166 asNanosDuration(vsyncPeriod));
167 }
168 }
169
170 static constexpr const int kLogIntervalSeconds = 60;
171 if (now > (previousLog + std::chrono::seconds(kLogIntervalSeconds))) {
172 DEBUG_LOG("%s: for display:%" PRIu64 " send %" PRIu32
173 " in last %d seconds",
174 __FUNCTION__, mDisplayId, vsyncs, kLogIntervalSeconds);
175 previousLog = now;
176 vsyncs = 0;
177 }
178 ++vsyncs;
179 }
180
181 ALOGI("Vsync thread for display:%" PRId64 " finished", mDisplayId);
182 }
183
184 } // namespace aidl::android::hardware::graphics::composer3::impl
185