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 "DisplayEventDispatcher"
18
19 #include <cinttypes>
20 #include <cstdint>
21
22 #include <androidfw/DisplayEventDispatcher.h>
23 #include <gui/DisplayEventReceiver.h>
24 #include <utils/Log.h>
25 #include <utils/Looper.h>
26
27 #include <utils/Timers.h>
28
29 namespace android {
30
31 // Number of events to read at a time from the DisplayEventDispatcher pipe.
32 // The value should be large enough that we can quickly drain the pipe
33 // using just a few large reads.
34 static const size_t EVENT_BUFFER_SIZE = 100;
35
DisplayEventDispatcher(const sp<Looper> & looper)36 DisplayEventDispatcher::DisplayEventDispatcher(const sp<Looper>& looper) :
37 mLooper(looper), mWaitingForVsync(false) {
38 ALOGV("dispatcher %p ~ Initializing display event dispatcher.", this);
39 }
40
initialize()41 status_t DisplayEventDispatcher::initialize() {
42 status_t result = mReceiver.initCheck();
43 if (result) {
44 ALOGW("Failed to initialize display event receiver, status=%d", result);
45 return result;
46 }
47
48 int rc = mLooper->addFd(mReceiver.getFd(), 0, Looper::EVENT_INPUT,
49 this, NULL);
50 if (rc < 0) {
51 return UNKNOWN_ERROR;
52 }
53 return OK;
54 }
55
dispose()56 void DisplayEventDispatcher::dispose() {
57 ALOGV("dispatcher %p ~ Disposing display event dispatcher.", this);
58
59 if (!mReceiver.initCheck()) {
60 mLooper->removeFd(mReceiver.getFd());
61 }
62 }
63
scheduleVsync()64 status_t DisplayEventDispatcher::scheduleVsync() {
65 if (!mWaitingForVsync) {
66 ALOGV("dispatcher %p ~ Scheduling vsync.", this);
67
68 // Drain all pending events.
69 nsecs_t vsyncTimestamp;
70 int32_t vsyncDisplayId;
71 uint32_t vsyncCount;
72 if (processPendingEvents(&vsyncTimestamp, &vsyncDisplayId, &vsyncCount)) {
73 ALOGE("dispatcher %p ~ last event processed while scheduling was for %" PRId64 "",
74 this, ns2ms(static_cast<nsecs_t>(vsyncTimestamp)));
75 }
76
77 status_t status = mReceiver.requestNextVsync();
78 if (status) {
79 ALOGW("Failed to request next vsync, status=%d", status);
80 return status;
81 }
82
83 mWaitingForVsync = true;
84 }
85 return OK;
86 }
87
handleEvent(int,int events,void *)88 int DisplayEventDispatcher::handleEvent(int, int events, void*) {
89 if (events & (Looper::EVENT_ERROR | Looper::EVENT_HANGUP)) {
90 ALOGE("Display event receiver pipe was closed or an error occurred. "
91 "events=0x%x", events);
92 return 0; // remove the callback
93 }
94
95 if (!(events & Looper::EVENT_INPUT)) {
96 ALOGW("Received spurious callback for unhandled poll event. "
97 "events=0x%x", events);
98 return 1; // keep the callback
99 }
100
101 // Drain all pending events, keep the last vsync.
102 nsecs_t vsyncTimestamp;
103 int32_t vsyncDisplayId;
104 uint32_t vsyncCount;
105 if (processPendingEvents(&vsyncTimestamp, &vsyncDisplayId, &vsyncCount)) {
106 ALOGV("dispatcher %p ~ Vsync pulse: timestamp=%" PRId64 ", id=%d, count=%d",
107 this, ns2ms(vsyncTimestamp), vsyncDisplayId, vsyncCount);
108 mWaitingForVsync = false;
109 dispatchVsync(vsyncTimestamp, vsyncDisplayId, vsyncCount);
110 }
111
112 return 1; // keep the callback
113 }
114
processPendingEvents(nsecs_t * outTimestamp,int32_t * outId,uint32_t * outCount)115 bool DisplayEventDispatcher::processPendingEvents(
116 nsecs_t* outTimestamp, int32_t* outId, uint32_t* outCount) {
117 bool gotVsync = false;
118 DisplayEventReceiver::Event buf[EVENT_BUFFER_SIZE];
119 ssize_t n;
120 while ((n = mReceiver.getEvents(buf, EVENT_BUFFER_SIZE)) > 0) {
121 ALOGV("dispatcher %p ~ Read %d events.", this, int(n));
122 for (ssize_t i = 0; i < n; i++) {
123 const DisplayEventReceiver::Event& ev = buf[i];
124 switch (ev.header.type) {
125 case DisplayEventReceiver::DISPLAY_EVENT_VSYNC:
126 // Later vsync events will just overwrite the info from earlier
127 // ones. That's fine, we only care about the most recent.
128 gotVsync = true;
129 *outTimestamp = ev.header.timestamp;
130 *outId = ev.header.id;
131 *outCount = ev.vsync.count;
132 break;
133 case DisplayEventReceiver::DISPLAY_EVENT_HOTPLUG:
134 dispatchHotplug(ev.header.timestamp, ev.header.id, ev.hotplug.connected);
135 break;
136 default:
137 ALOGW("dispatcher %p ~ ignoring unknown event type %#x", this, ev.header.type);
138 break;
139 }
140 }
141 }
142 if (n < 0) {
143 ALOGW("Failed to get events from display event dispatcher, status=%d", status_t(n));
144 }
145 return gotVsync;
146 }
147 }
148