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 DISPLAY_EVENT_NULL = fourcc('n', 'u', 'l', 'l'),
57 };
58
59 struct Event {
60
61 struct Header {
62 uint32_t type;
63 PhysicalDisplayId displayId;
64 nsecs_t timestamp __attribute__((aligned(8)));
65 };
66
67 struct VSync {
68 uint32_t count;
69 nsecs_t expectedVSyncTimestamp;
70 };
71
72 struct Hotplug {
73 bool connected;
74 };
75
76 struct Config {
77 int32_t configId;
78 nsecs_t vsyncPeriod;
79 };
80
81 Header header;
82 union {
83 VSync vsync;
84 Hotplug hotplug;
85 Config config;
86 };
87 };
88
89 public:
90 /*
91 * DisplayEventReceiver creates and registers an event connection with
92 * SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate
93 * or requestNextVsync to receive them.
94 * To receive Config Changed events specify this in the constructor.
95 * Other events start being delivered immediately.
96 */
97 explicit DisplayEventReceiver(
98 ISurfaceComposer::VsyncSource vsyncSource = ISurfaceComposer::eVsyncSourceApp,
99 ISurfaceComposer::ConfigChanged configChanged =
100 ISurfaceComposer::eConfigChangedSuppress);
101
102 /*
103 * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events
104 * stop being delivered immediately. Note that the queue could have
105 * some events pending. These will be delivered.
106 */
107 ~DisplayEventReceiver();
108
109 /*
110 * initCheck returns the state of DisplayEventReceiver after construction.
111 */
112 status_t initCheck() const;
113
114 /*
115 * getFd returns the file descriptor to use to receive events.
116 * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this
117 * file-descriptor.
118 */
119 int getFd() const;
120
121 /*
122 * getEvents reads events from the queue and returns how many events were
123 * read. Returns 0 if there are no more events or a negative error code.
124 * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it
125 * should be destroyed and getEvents() shouldn't be called again.
126 */
127 ssize_t getEvents(Event* events, size_t count);
128 static ssize_t getEvents(gui::BitTube* dataChannel, Event* events, size_t count);
129
130 /*
131 * sendEvents write events to the queue and returns how many events were
132 * written.
133 */
134 ssize_t sendEvents(Event const* events, size_t count);
135 static ssize_t sendEvents(gui::BitTube* dataChannel, Event const* events, size_t count);
136
137 /*
138 * setVsyncRate() sets the Event::VSync delivery rate. A value of
139 * 1 returns every Event::VSync. A value of 2 returns every other event,
140 * etc... a value of 0 returns no event unless requestNextVsync() has
141 * been called.
142 */
143 status_t setVsyncRate(uint32_t count);
144
145 /*
146 * requestNextVsync() schedules the next Event::VSync. It has no effect
147 * if the vsync rate is > 0.
148 */
149 status_t requestNextVsync();
150
151 private:
152 sp<IDisplayEventConnection> mEventConnection;
153 std::unique_ptr<gui::BitTube> mDataChannel;
154 };
155
156 // ----------------------------------------------------------------------------
157 }; // namespace android
158
159 #endif // ANDROID_GUI_DISPLAY_EVENT_H
160