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 <ftl/flags.h>
24
25 #include <utils/Errors.h>
26 #include <utils/RefBase.h>
27 #include <utils/Timers.h>
28
29 #include <android/gui/ISurfaceComposer.h>
30 #include <binder/IInterface.h>
31 #include <gui/VsyncEventData.h>
32
33 #include <ui/DisplayId.h>
34
35 // ----------------------------------------------------------------------------
36
37 namespace android {
38
39 // ----------------------------------------------------------------------------
40
41 using EventRegistrationFlags = ftl::Flags<gui::ISurfaceComposer::EventRegistration>;
42
43 using gui::IDisplayEventConnection;
44 using gui::ParcelableVsyncEventData;
45 using gui::VsyncEventData;
46
47 namespace gui {
48 class BitTube;
49 } // namespace gui
50
fourcc(char c1,char c2,char c3,char c4)51 static inline constexpr uint32_t fourcc(char c1, char c2, char c3, char c4) {
52 return static_cast<uint32_t>(c1) << 24 |
53 static_cast<uint32_t>(c2) << 16 |
54 static_cast<uint32_t>(c3) << 8 |
55 static_cast<uint32_t>(c4);
56 }
57
58 // ----------------------------------------------------------------------------
59 class DisplayEventReceiver {
60 public:
61 enum {
62 DISPLAY_EVENT_VSYNC = fourcc('v', 's', 'y', 'n'),
63 DISPLAY_EVENT_HOTPLUG = fourcc('p', 'l', 'u', 'g'),
64 DISPLAY_EVENT_MODE_CHANGE = fourcc('m', 'o', 'd', 'e'),
65 DISPLAY_EVENT_NULL = fourcc('n', 'u', 'l', 'l'),
66 DISPLAY_EVENT_FRAME_RATE_OVERRIDE = fourcc('r', 'a', 't', 'e'),
67 DISPLAY_EVENT_FRAME_RATE_OVERRIDE_FLUSH = fourcc('f', 'l', 's', 'h'),
68 DISPLAY_EVENT_HDCP_LEVELS_CHANGE = fourcc('h', 'd', 'c', 'p'),
69 };
70
71 struct Event {
72 // We add __attribute__((aligned(8))) for nsecs_t fields because
73 // we need to make sure all fields are aligned the same with x86
74 // and x64 (long long has different default alignment):
75 //
76 // https://en.wikipedia.org/wiki/Data_structure_alignment
77
78 struct Header {
79 uint32_t type;
80 PhysicalDisplayId displayId __attribute__((aligned(8)));
81 nsecs_t timestamp __attribute__((aligned(8)));
82 };
83
84 struct VSync {
85 uint32_t count;
86 VsyncEventData vsyncData;
87 };
88
89 struct Hotplug {
90 bool connected;
91 int32_t connectionError __attribute__((aligned(4)));
92 };
93
94 struct ModeChange {
95 int32_t modeId;
96 nsecs_t vsyncPeriod __attribute__((aligned(8)));
97 };
98
99 struct FrameRateOverride {
100 uid_t uid __attribute__((aligned(8)));
101 float frameRateHz __attribute__((aligned(8)));
102 };
103
104 /*
105 * The values are defined in aidl:
106 * hardware/interfaces/drm/aidl/android/hardware/drm/HdcpLevel.aidl
107 */
108 struct HdcpLevelsChange {
109 int32_t connectedLevel;
110 int32_t maxLevel;
111 };
112
113 Header header;
114 union {
115 VSync vsync;
116 Hotplug hotplug;
117 ModeChange modeChange;
118 FrameRateOverride frameRateOverride;
119 HdcpLevelsChange hdcpLevelsChange;
120 };
121 };
122 static_assert(sizeof(Event) == 216);
123
124 public:
125 /*
126 * DisplayEventReceiver creates and registers an event connection with
127 * SurfaceFlinger. VSync events are disabled by default. Call setVSyncRate
128 * or requestNextVsync to receive them.
129 * To receive ModeChanged and/or FrameRateOverrides events specify this in
130 * the constructor. Other events start being delivered immediately.
131 */
132 explicit DisplayEventReceiver(gui::ISurfaceComposer::VsyncSource vsyncSource =
133 gui::ISurfaceComposer::VsyncSource::eVsyncSourceApp,
134 EventRegistrationFlags eventRegistration = {},
135 const sp<IBinder>& layerHandle = nullptr);
136
137 /*
138 * ~DisplayEventReceiver severs the connection with SurfaceFlinger, new events
139 * stop being delivered immediately. Note that the queue could have
140 * some events pending. These will be delivered.
141 */
142 ~DisplayEventReceiver();
143
144 /*
145 * initCheck returns the state of DisplayEventReceiver after construction.
146 */
147 status_t initCheck() const;
148
149 /*
150 * getFd returns the file descriptor to use to receive events.
151 * OWNERSHIP IS RETAINED by DisplayEventReceiver. DO NOT CLOSE this
152 * file-descriptor.
153 */
154 int getFd() const;
155
156 /*
157 * getEvents reads events from the queue and returns how many events were
158 * read. Returns 0 if there are no more events or a negative error code.
159 * If NOT_ENOUGH_DATA is returned, the object has become invalid forever, it
160 * should be destroyed and getEvents() shouldn't be called again.
161 */
162 ssize_t getEvents(Event* events, size_t count);
163 static ssize_t getEvents(gui::BitTube* dataChannel, Event* events, size_t count);
164
165 /*
166 * sendEvents write events to the queue and returns how many events were
167 * written.
168 */
169 ssize_t sendEvents(Event const* events, size_t count);
170 static ssize_t sendEvents(gui::BitTube* dataChannel, Event const* events, size_t count);
171
172 /*
173 * setVsyncRate() sets the Event::VSync delivery rate. A value of
174 * 1 returns every Event::VSync. A value of 2 returns every other event,
175 * etc... a value of 0 returns no event unless requestNextVsync() has
176 * been called.
177 */
178 status_t setVsyncRate(uint32_t count);
179
180 /*
181 * requestNextVsync() schedules the next Event::VSync. It has no effect
182 * if the vsync rate is > 0.
183 */
184 status_t requestNextVsync();
185
186 /**
187 * getLatestVsyncEventData() gets the latest vsync event data.
188 */
189 status_t getLatestVsyncEventData(ParcelableVsyncEventData* outVsyncEventData) const;
190
191 private:
192 sp<IDisplayEventConnection> mEventConnection;
193 std::unique_ptr<gui::BitTube> mDataChannel;
194 std::optional<status_t> mInitError;
195 };
196
197 inline bool operator==(DisplayEventReceiver::Event::FrameRateOverride lhs,
198 DisplayEventReceiver::Event::FrameRateOverride rhs) {
199 return (lhs.uid == rhs.uid) && std::abs(lhs.frameRateHz - rhs.frameRateHz) < 0.001f;
200 }
201
202 // ----------------------------------------------------------------------------
203 }; // namespace android
204
205 #endif // ANDROID_GUI_DISPLAY_EVENT_H
206