1 /*
2 * Copyright (C) 2015 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 #define LOG_TAG "drmhwc"
18
19 #include "VSyncWorker.h"
20
21 #include <xf86drm.h>
22 #include <xf86drmMode.h>
23
24 #include <cstdlib>
25 #include <cstring>
26 #include <ctime>
27
28 #include "drm/ResourceManager.h"
29 #include "utils/log.h"
30
31 namespace android {
32
CreateInstance(std::shared_ptr<DrmDisplayPipeline> & pipe,VSyncWorkerCallbacks & callbacks)33 auto VSyncWorker::CreateInstance(std::shared_ptr<DrmDisplayPipeline> &pipe,
34 VSyncWorkerCallbacks &callbacks)
35 -> std::shared_ptr<VSyncWorker> {
36 auto vsw = std::shared_ptr<VSyncWorker>(new VSyncWorker());
37
38 vsw->callbacks_ = callbacks;
39
40 if (pipe) {
41 vsw->high_crtc_ = pipe->crtc->Get()->GetIndexInResArray()
42 << DRM_VBLANK_HIGH_CRTC_SHIFT;
43 vsw->drm_fd_ = pipe->device->GetFd();
44 }
45
46 std::thread(&VSyncWorker::ThreadFn, vsw.get(), vsw).detach();
47
48 return vsw;
49 }
50
VSyncControl(bool enabled)51 void VSyncWorker::VSyncControl(bool enabled) {
52 {
53 const std::lock_guard<std::mutex> lock(mutex_);
54 enabled_ = enabled;
55 last_timestamp_ = -1;
56 }
57
58 cv_.notify_all();
59 }
60
StopThread()61 void VSyncWorker::StopThread() {
62 {
63 const std::lock_guard<std::mutex> lock(mutex_);
64 thread_exit_ = true;
65 enabled_ = false;
66 callbacks_ = {};
67 }
68
69 cv_.notify_all();
70 }
71
72 /*
73 * Returns the timestamp of the next vsync in phase with last_timestamp_.
74 * For example:
75 * last_timestamp_ = 137
76 * frame_ns = 50
77 * current = 683
78 *
79 * ret = (50 * ((683 - 137)/50 + 1)) + 137
80 * ret = 687
81 *
82 * Thus, we must sleep until timestamp 687 to maintain phase with the last
83 * timestamp.
84 */
GetPhasedVSync(int64_t frame_ns,int64_t current) const85 int64_t VSyncWorker::GetPhasedVSync(int64_t frame_ns, int64_t current) const {
86 if (last_timestamp_ < 0)
87 return current + frame_ns;
88
89 return frame_ns * ((current - last_timestamp_) / frame_ns + 1) +
90 last_timestamp_;
91 }
92
93 static const int64_t kOneSecondNs = 1LL * 1000 * 1000 * 1000;
94
SyntheticWaitVBlank(int64_t * timestamp)95 int VSyncWorker::SyntheticWaitVBlank(int64_t *timestamp) {
96 auto time_now = ResourceManager::GetTimeMonotonicNs();
97
98 // Default to 60Hz refresh rate
99 constexpr uint32_t kDefaultVSPeriodNs = 16666666;
100 auto period_ns = kDefaultVSPeriodNs;
101 if (callbacks_.get_vperiod_ns && callbacks_.get_vperiod_ns() != 0)
102 period_ns = callbacks_.get_vperiod_ns();
103
104 auto phased_timestamp = GetPhasedVSync(period_ns, time_now);
105 struct timespec vsync {};
106 vsync.tv_sec = int(phased_timestamp / kOneSecondNs);
107 vsync.tv_nsec = int(phased_timestamp - (vsync.tv_sec * kOneSecondNs));
108
109 int ret = 0;
110 do {
111 ret = clock_nanosleep(CLOCK_MONOTONIC, TIMER_ABSTIME, &vsync, nullptr);
112 } while (ret == EINTR);
113 if (ret != 0)
114 return ret;
115
116 *timestamp = phased_timestamp;
117 return 0;
118 }
119
ThreadFn(const std::shared_ptr<VSyncWorker> & vsw)120 void VSyncWorker::ThreadFn(const std::shared_ptr<VSyncWorker> &vsw) {
121 int ret = 0;
122
123 for (;;) {
124 {
125 std::unique_lock<std::mutex> lock(vsw->mutex_);
126 if (thread_exit_)
127 break;
128
129 if (!enabled_)
130 vsw->cv_.wait(lock);
131
132 if (!enabled_)
133 continue;
134 }
135
136 ret = -EAGAIN;
137 int64_t timestamp = 0;
138 drmVBlank vblank{};
139
140 if (drm_fd_) {
141 vblank.request.type = (drmVBlankSeqType)(DRM_VBLANK_RELATIVE |
142 (high_crtc_ &
143 DRM_VBLANK_HIGH_CRTC_MASK));
144 vblank.request.sequence = 1;
145
146 ret = drmWaitVBlank(*drm_fd_, &vblank);
147 if (ret == -EINTR)
148 continue;
149 }
150
151 if (ret != 0) {
152 ret = SyntheticWaitVBlank(×tamp);
153 if (ret != 0)
154 continue;
155 } else {
156 constexpr int kUsToNsMul = 1000;
157 timestamp = (int64_t)vblank.reply.tval_sec * kOneSecondNs +
158 (int64_t)vblank.reply.tval_usec * kUsToNsMul;
159 }
160
161 decltype(callbacks_.out_event) callback;
162
163 {
164 const std::lock_guard<std::mutex> lock(mutex_);
165 if (!enabled_)
166 continue;
167 callback = callbacks_.out_event;
168 }
169
170 if (callback)
171 callback(timestamp);
172
173 last_timestamp_ = timestamp;
174 }
175
176 ALOGI("VSyncWorker thread exit");
177 }
178 } // namespace android
179