1 /*
2 * Copyright (C) 2011 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 #ifndef ANDROID_GUI_DISPLAY_EVENT_H
18 #define ANDROID_GUI_DISPLAY_EVENT_H
19
20 #include <stdint.h>
21 #include <sys/types.h>
22
23 #include <utils/Errors.h>
24 #include <utils/RefBase.h>
25 #include <utils/Timers.h>
26
27 #include <binder/IInterface.h>
28 #include <gui/ISurfaceComposer.h>
29
30 // ----------------------------------------------------------------------------
31
32 namespace android {
33
34 // ----------------------------------------------------------------------------
35
36 class IDisplayEventConnection;
37
38 namespace gui {
39 class BitTube;
40 } // namespace gui
41
fourcc(char c1,char c2,char c3,char c4)42 static inline constexpr uint32_t fourcc(char c1, char c2, char c3, char c4) {
43 return static_cast<uint32_t>(c1) << 24 |
44 static_cast<uint32_t>(c2) << 16 |
45 static_cast<uint32_t>(c3) << 8 |
46 static_cast<uint32_t>(c4);
47 }
48
49 // ----------------------------------------------------------------------------
50 class DisplayEventReceiver {
51 public:
52 enum {
53 DISPLAY_EVENT_VSYNC = fourcc('v', 's', 'y', 'n'),
54 DISPLAY_EVENT_HOTPLUG = fourcc('p', 'l', 'u', 'g'),
55 DISPLAY_EVENT_CONFIG_CHANGED = fourcc('c', 'o', 'n', 'f'),
56 };
57
58 struct Event {
59
60 struct Header {
61 uint32_t type;
62 PhysicalDisplayId displayId;
63 nsecs_t timestamp __attribute__((aligned(8)));
64 };
65
66 struct VSync {
67 uint32_t count;
68 nsecs_t expectedVSyncTimestamp;
69 };
70
71 struct Hotplug {
72 bool connected;
73 };
74
75 struct Config {
76 int32_t configId;
77 nsecs_t vsyncPeriod;
78 };
79
80 Header header;
81 union {
82 VSync vsync;
83 Hotplug hotplug;
84 Config config;
85 };
86 };
87
88 public:
89 /*
90 * DisplayEventReceiver creates and registers an event connection with
91 * SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate
92 * or requestNextVsync to receive them.
93 * To receive Config Changed events specify this in the constructor.
94 * Other events start being delivered immediately.
95 */
96 explicit DisplayEventReceiver(
97 ISurfaceComposer::VsyncSource vsyncSource = ISurfaceComposer::eVsyncSourceApp,
98 ISurfaceComposer::ConfigChanged configChanged =
99 ISurfaceComposer::eConfigChangedSuppress);
100
101 /*
102 * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events
103 * stop being delivered immediately. Note that the queue could have
104 * some events pending. These will be delivered.
105 */
106 ~DisplayEventReceiver();
107
108 /*
109 * initCheck returns the state of DisplayEventReceiver after construction.
110 */
111 status_t initCheck() const;
112
113 /*
114 * getFd returns the file descriptor to use to receive events.
115 * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this
116 * file-descriptor.
117 */
118 int getFd() const;
119
120 /*
121 * getEvents reads events from the queue and returns how many events were
122 * read. Returns 0 if there are no more events or a negative error code.
123 * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it
124 * should be destroyed and getEvents() shouldn't be called again.
125 */
126 ssize_t getEvents(Event* events, size_t count);
127 static ssize_t getEvents(gui::BitTube* dataChannel, Event* events, size_t count);
128
129 /*
130 * sendEvents write events to the queue and returns how many events were
131 * written.
132 */
133 static ssize_t sendEvents(gui::BitTube* dataChannel, Event const* events, size_t count);
134
135 /*
136 * setVsyncRate() sets the Event::VSync delivery rate. A value of
137 * 1 returns every Event::VSync. A value of 2 returns every other event,
138 * etc... a value of 0 returns no event unless requestNextVsync() has
139 * been called.
140 */
141 status_t setVsyncRate(uint32_t count);
142
143 /*
144 * requestNextVsync() schedules the next Event::VSync. It has no effect
145 * if the vsync rate is > 0.
146 */
147 status_t requestNextVsync();
148
149 /*
150 * requestLatestConfig() force-requests the current config for the primary
151 * display.
152 */
153 status_t requestLatestConfig();
154
155 private:
156 sp<IDisplayEventConnection> mEventConnection;
157 std::unique_ptr<gui::BitTube> mDataChannel;
158 };
159
160 // ----------------------------------------------------------------------------
161 }; // namespace android
162
163 #endif // ANDROID_GUI_DISPLAY_EVENT_H
164