| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 1 | /* | 
|  | 2 | * Copyright 2016 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 | #pragma once | 
|  | 18 |  | 
|  | 19 | #include "ComposerHal.h" | 
|  | 20 |  | 
|  | 21 | #include <optional> | 
|  | 22 | #include <string> | 
|  | 23 | #include <unordered_map> | 
|  | 24 | #include <utility> | 
|  | 25 | #include <vector> | 
|  | 26 |  | 
|  | 27 | // TODO(b/129481165): remove the #pragma below and fix conversion issues | 
|  | 28 | #pragma clang diagnostic push | 
|  | 29 | #pragma clang diagnostic ignored "-Wconversion" | 
|  | 30 | #pragma clang diagnostic ignored "-Wextra" | 
|  | 31 |  | 
|  | 32 | #include <composer-command-buffer/2.4/ComposerCommandBuffer.h> | 
|  | 33 | #include <gui/BufferQueue.h> | 
|  | 34 | #include <gui/HdrMetadata.h> | 
|  | 35 | #include <math/mat4.h> | 
|  | 36 | #include <ui/DisplayedFrameStats.h> | 
|  | 37 | #include <ui/GraphicBuffer.h> | 
|  | 38 | #include <utils/StrongPointer.h> | 
|  | 39 |  | 
| Leon Scroggins III | 2e1aa18 | 2021-12-01 17:33:12 -0500 | [diff] [blame] | 40 | #include <aidl/android/hardware/graphics/composer3/Composition.h> | 
|  | 41 |  | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 42 | // TODO(b/129481165): remove the #pragma below and fix conversion issues | 
|  | 43 | #pragma clang diagnostic pop // ignored "-Wconversion -Wextra" | 
|  | 44 |  | 
|  | 45 | namespace android::Hwc2 { | 
|  | 46 |  | 
|  | 47 | namespace types = hardware::graphics::common; | 
|  | 48 |  | 
|  | 49 | namespace V2_1 = hardware::graphics::composer::V2_1; | 
|  | 50 | namespace V2_2 = hardware::graphics::composer::V2_2; | 
|  | 51 | namespace V2_3 = hardware::graphics::composer::V2_3; | 
|  | 52 | namespace V2_4 = hardware::graphics::composer::V2_4; | 
|  | 53 |  | 
|  | 54 | using types::V1_0::ColorTransform; | 
|  | 55 | using types::V1_0::Transform; | 
|  | 56 | using types::V1_1::RenderIntent; | 
|  | 57 | using types::V1_2::ColorMode; | 
|  | 58 | using types::V1_2::Dataspace; | 
|  | 59 | using types::V1_2::Hdr; | 
|  | 60 | using types::V1_2::PixelFormat; | 
|  | 61 |  | 
|  | 62 | using V2_1::Config; | 
|  | 63 | using V2_1::Display; | 
|  | 64 | using V2_1::Error; | 
|  | 65 | using V2_1::Layer; | 
|  | 66 | using V2_4::CommandReaderBase; | 
|  | 67 | using V2_4::CommandWriterBase; | 
|  | 68 | using V2_4::IComposer; | 
|  | 69 | using V2_4::IComposerCallback; | 
|  | 70 | using V2_4::IComposerClient; | 
|  | 71 | using V2_4::VsyncPeriodChangeTimeline; | 
|  | 72 | using V2_4::VsyncPeriodNanos; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 73 | using PerFrameMetadata = IComposerClient::PerFrameMetadata; | 
|  | 74 | using PerFrameMetadataKey = IComposerClient::PerFrameMetadataKey; | 
|  | 75 | using PerFrameMetadataBlob = IComposerClient::PerFrameMetadataBlob; | 
|  | 76 |  | 
|  | 77 | class CommandReader : public CommandReaderBase { | 
|  | 78 | public: | 
|  | 79 | ~CommandReader(); | 
|  | 80 |  | 
|  | 81 | // Parse and execute commands from the command queue.  The commands are | 
|  | 82 | // actually return values from the server and will be saved in ReturnData. | 
|  | 83 | Error parse(); | 
|  | 84 |  | 
|  | 85 | // Get and clear saved errors. | 
|  | 86 | struct CommandError { | 
|  | 87 | uint32_t location; | 
|  | 88 | Error error; | 
|  | 89 | }; | 
|  | 90 | std::vector<CommandError> takeErrors(); | 
|  | 91 |  | 
|  | 92 | bool hasChanges(Display display, uint32_t* outNumChangedCompositionTypes, | 
|  | 93 | uint32_t* outNumLayerRequestMasks) const; | 
|  | 94 |  | 
|  | 95 | // Get and clear saved changed composition types. | 
| Leon Scroggins III | 2e1aa18 | 2021-12-01 17:33:12 -0500 | [diff] [blame] | 96 | void takeChangedCompositionTypes( | 
|  | 97 | Display display, std::vector<Layer>* outLayers, | 
|  | 98 | std::vector<aidl::android::hardware::graphics::composer3::Composition>* outTypes); | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 99 |  | 
|  | 100 | // Get and clear saved display requests. | 
|  | 101 | void takeDisplayRequests(Display display, uint32_t* outDisplayRequestMask, | 
|  | 102 | std::vector<Layer>* outLayers, | 
|  | 103 | std::vector<uint32_t>* outLayerRequestMasks); | 
|  | 104 |  | 
|  | 105 | // Get and clear saved release fences. | 
|  | 106 | void takeReleaseFences(Display display, std::vector<Layer>* outLayers, | 
|  | 107 | std::vector<int>* outReleaseFences); | 
|  | 108 |  | 
|  | 109 | // Get and clear saved present fence. | 
|  | 110 | void takePresentFence(Display display, int* outPresentFence); | 
|  | 111 |  | 
|  | 112 | // Get what stage succeeded during PresentOrValidate: Present or Validate | 
|  | 113 | void takePresentOrValidateStage(Display display, uint32_t* state); | 
|  | 114 |  | 
|  | 115 | // Get the client target properties requested by hardware composer. | 
|  | 116 | void takeClientTargetProperty(Display display, | 
|  | 117 | IComposerClient::ClientTargetProperty* outClientTargetProperty); | 
|  | 118 |  | 
|  | 119 | private: | 
|  | 120 | void resetData(); | 
|  | 121 |  | 
|  | 122 | bool parseSelectDisplay(uint16_t length); | 
|  | 123 | bool parseSetError(uint16_t length); | 
|  | 124 | bool parseSetChangedCompositionTypes(uint16_t length); | 
|  | 125 | bool parseSetDisplayRequests(uint16_t length); | 
|  | 126 | bool parseSetPresentFence(uint16_t length); | 
|  | 127 | bool parseSetReleaseFences(uint16_t length); | 
|  | 128 | bool parseSetPresentOrValidateDisplayResult(uint16_t length); | 
|  | 129 | bool parseSetClientTargetProperty(uint16_t length); | 
|  | 130 |  | 
|  | 131 | struct ReturnData { | 
|  | 132 | uint32_t displayRequests = 0; | 
|  | 133 |  | 
|  | 134 | std::vector<Layer> changedLayers; | 
| Leon Scroggins III | 2e1aa18 | 2021-12-01 17:33:12 -0500 | [diff] [blame] | 135 | std::vector<aidl::android::hardware::graphics::composer3::Composition> compositionTypes; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 136 |  | 
|  | 137 | std::vector<Layer> requestedLayers; | 
|  | 138 | std::vector<uint32_t> requestMasks; | 
|  | 139 |  | 
|  | 140 | int presentFence = -1; | 
|  | 141 |  | 
|  | 142 | std::vector<Layer> releasedLayers; | 
|  | 143 | std::vector<int> releaseFences; | 
|  | 144 |  | 
|  | 145 | uint32_t presentOrValidateState; | 
|  | 146 |  | 
|  | 147 | // Composer 2.4 implementation can return a client target property | 
|  | 148 | // structure to indicate the client target properties that hardware | 
|  | 149 | // composer requests. The composer client must change the client target | 
|  | 150 | // properties to match this request. | 
|  | 151 | IComposerClient::ClientTargetProperty clientTargetProperty{PixelFormat::RGBA_8888, | 
|  | 152 | Dataspace::UNKNOWN}; | 
|  | 153 | }; | 
|  | 154 |  | 
|  | 155 | std::vector<CommandError> mErrors; | 
|  | 156 | std::unordered_map<Display, ReturnData> mReturnData; | 
|  | 157 |  | 
|  | 158 | // When SELECT_DISPLAY is parsed, this is updated to point to the | 
|  | 159 | // display's return data in mReturnData.  We use it to avoid repeated | 
|  | 160 | // map lookups. | 
|  | 161 | ReturnData* mCurrentReturnData; | 
|  | 162 | }; | 
|  | 163 |  | 
|  | 164 | // Composer is a wrapper to IComposer, a proxy to server-side composer. | 
|  | 165 | class HidlComposer final : public Composer { | 
|  | 166 | public: | 
|  | 167 | explicit HidlComposer(const std::string& serviceName); | 
|  | 168 | ~HidlComposer() override; | 
|  | 169 |  | 
| Ady Abraham | 4d211cf | 2021-12-14 16:19:03 -0800 | [diff] [blame] | 170 | bool isSupported(OptionalFeature) const; | 
|  | 171 |  | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 172 | std::vector<IComposer::Capability> getCapabilities() override; | 
|  | 173 | std::string dumpDebugInfo() override; | 
|  | 174 |  | 
|  | 175 | void registerCallback(const sp<IComposerCallback>& callback) override; | 
|  | 176 |  | 
|  | 177 | // Reset all pending commands in the command buffer. Useful if you want to | 
|  | 178 | // skip a frame but have already queued some commands. | 
|  | 179 | void resetCommands() override; | 
|  | 180 |  | 
|  | 181 | // Explicitly flush all pending commands in the command buffer. | 
|  | 182 | Error executeCommands() override; | 
|  | 183 |  | 
|  | 184 | uint32_t getMaxVirtualDisplayCount() override; | 
|  | 185 | Error createVirtualDisplay(uint32_t width, uint32_t height, PixelFormat* format, | 
|  | 186 | Display* outDisplay) override; | 
|  | 187 | Error destroyVirtualDisplay(Display display) override; | 
|  | 188 |  | 
|  | 189 | Error acceptDisplayChanges(Display display) override; | 
|  | 190 |  | 
|  | 191 | Error createLayer(Display display, Layer* outLayer) override; | 
|  | 192 | Error destroyLayer(Display display, Layer layer) override; | 
|  | 193 |  | 
|  | 194 | Error getActiveConfig(Display display, Config* outConfig) override; | 
| Leon Scroggins III | 2e1aa18 | 2021-12-01 17:33:12 -0500 | [diff] [blame] | 195 | Error getChangedCompositionTypes( | 
|  | 196 | Display display, std::vector<Layer>* outLayers, | 
|  | 197 | std::vector<aidl::android::hardware::graphics::composer3::Composition>* outTypes) | 
|  | 198 | override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 199 | Error getColorModes(Display display, std::vector<ColorMode>* outModes) override; | 
|  | 200 | Error getDisplayAttribute(Display display, Config config, IComposerClient::Attribute attribute, | 
|  | 201 | int32_t* outValue) override; | 
|  | 202 | Error getDisplayConfigs(Display display, std::vector<Config>* outConfigs); | 
|  | 203 | Error getDisplayName(Display display, std::string* outName) override; | 
|  | 204 |  | 
|  | 205 | Error getDisplayRequests(Display display, uint32_t* outDisplayRequestMask, | 
|  | 206 | std::vector<Layer>* outLayers, | 
|  | 207 | std::vector<uint32_t>* outLayerRequestMasks) override; | 
|  | 208 |  | 
|  | 209 | Error getDozeSupport(Display display, bool* outSupport) override; | 
|  | 210 | Error getHdrCapabilities(Display display, std::vector<Hdr>* outTypes, float* outMaxLuminance, | 
|  | 211 | float* outMaxAverageLuminance, float* outMinLuminance) override; | 
|  | 212 |  | 
|  | 213 | Error getReleaseFences(Display display, std::vector<Layer>* outLayers, | 
|  | 214 | std::vector<int>* outReleaseFences) override; | 
|  | 215 |  | 
|  | 216 | Error presentDisplay(Display display, int* outPresentFence) override; | 
|  | 217 |  | 
|  | 218 | Error setActiveConfig(Display display, Config config) override; | 
|  | 219 |  | 
|  | 220 | /* | 
|  | 221 | * The composer caches client targets internally.  When target is nullptr, | 
|  | 222 | * the composer uses slot to look up the client target from its cache. | 
|  | 223 | * When target is not nullptr, the cache is updated with the new target. | 
|  | 224 | */ | 
|  | 225 | Error setClientTarget(Display display, uint32_t slot, const sp<GraphicBuffer>& target, | 
|  | 226 | int acquireFence, Dataspace dataspace, | 
|  | 227 | const std::vector<IComposerClient::Rect>& damage) override; | 
|  | 228 | Error setColorMode(Display display, ColorMode mode, RenderIntent renderIntent) override; | 
| Ady Abraham | dc011a9 | 2021-12-21 14:06:44 -0800 | [diff] [blame] | 229 | Error setColorTransform(Display display, const float* matrix) override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 230 | Error setOutputBuffer(Display display, const native_handle_t* buffer, | 
|  | 231 | int releaseFence) override; | 
|  | 232 | Error setPowerMode(Display display, IComposerClient::PowerMode mode) override; | 
|  | 233 | Error setVsyncEnabled(Display display, IComposerClient::Vsync enabled) override; | 
|  | 234 |  | 
|  | 235 | Error setClientTargetSlotCount(Display display) override; | 
|  | 236 |  | 
| Ady Abraham | 43065bd | 2021-12-10 17:22:15 -0800 | [diff] [blame] | 237 | Error validateDisplay(Display display, nsecs_t expectedPresentTime, uint32_t* outNumTypes, | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 238 | uint32_t* outNumRequests) override; | 
|  | 239 |  | 
| Ady Abraham | 43065bd | 2021-12-10 17:22:15 -0800 | [diff] [blame] | 240 | Error presentOrValidateDisplay(Display display, nsecs_t expectedPresentTime, | 
|  | 241 | uint32_t* outNumTypes, uint32_t* outNumRequests, | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 242 | int* outPresentFence, uint32_t* state) override; | 
|  | 243 |  | 
|  | 244 | Error setCursorPosition(Display display, Layer layer, int32_t x, int32_t y) override; | 
|  | 245 | /* see setClientTarget for the purpose of slot */ | 
|  | 246 | Error setLayerBuffer(Display display, Layer layer, uint32_t slot, | 
|  | 247 | const sp<GraphicBuffer>& buffer, int acquireFence) override; | 
|  | 248 | Error setLayerSurfaceDamage(Display display, Layer layer, | 
|  | 249 | const std::vector<IComposerClient::Rect>& damage) override; | 
|  | 250 | Error setLayerBlendMode(Display display, Layer layer, IComposerClient::BlendMode mode) override; | 
|  | 251 | Error setLayerColor(Display display, Layer layer, const IComposerClient::Color& color) override; | 
| Leon Scroggins III | 2e1aa18 | 2021-12-01 17:33:12 -0500 | [diff] [blame] | 252 | Error setLayerCompositionType( | 
|  | 253 | Display display, Layer layer, | 
|  | 254 | aidl::android::hardware::graphics::composer3::Composition type) override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 255 | Error setLayerDataspace(Display display, Layer layer, Dataspace dataspace) override; | 
|  | 256 | Error setLayerDisplayFrame(Display display, Layer layer, | 
|  | 257 | const IComposerClient::Rect& frame) override; | 
|  | 258 | Error setLayerPlaneAlpha(Display display, Layer layer, float alpha) override; | 
|  | 259 | Error setLayerSidebandStream(Display display, Layer layer, | 
|  | 260 | const native_handle_t* stream) override; | 
|  | 261 | Error setLayerSourceCrop(Display display, Layer layer, | 
|  | 262 | const IComposerClient::FRect& crop) override; | 
|  | 263 | Error setLayerTransform(Display display, Layer layer, Transform transform) override; | 
|  | 264 | Error setLayerVisibleRegion(Display display, Layer layer, | 
|  | 265 | const std::vector<IComposerClient::Rect>& visible) override; | 
|  | 266 | Error setLayerZOrder(Display display, Layer layer, uint32_t z) override; | 
|  | 267 |  | 
|  | 268 | // Composer HAL 2.2 | 
|  | 269 | Error setLayerPerFrameMetadata( | 
|  | 270 | Display display, Layer layer, | 
|  | 271 | const std::vector<IComposerClient::PerFrameMetadata>& perFrameMetadatas) override; | 
|  | 272 | std::vector<IComposerClient::PerFrameMetadataKey> getPerFrameMetadataKeys( | 
|  | 273 | Display display) override; | 
|  | 274 | Error getRenderIntents(Display display, ColorMode colorMode, | 
|  | 275 | std::vector<RenderIntent>* outRenderIntents) override; | 
|  | 276 | Error getDataspaceSaturationMatrix(Dataspace dataspace, mat4* outMatrix) override; | 
|  | 277 |  | 
|  | 278 | // Composer HAL 2.3 | 
|  | 279 | Error getDisplayIdentificationData(Display display, uint8_t* outPort, | 
|  | 280 | std::vector<uint8_t>* outData) override; | 
|  | 281 | Error setLayerColorTransform(Display display, Layer layer, const float* matrix) override; | 
|  | 282 | Error getDisplayedContentSamplingAttributes(Display display, PixelFormat* outFormat, | 
|  | 283 | Dataspace* outDataspace, | 
|  | 284 | uint8_t* outComponentMask) override; | 
|  | 285 | Error setDisplayContentSamplingEnabled(Display display, bool enabled, uint8_t componentMask, | 
|  | 286 | uint64_t maxFrames) override; | 
|  | 287 | Error getDisplayedContentSample(Display display, uint64_t maxFrames, uint64_t timestamp, | 
|  | 288 | DisplayedFrameStats* outStats) override; | 
|  | 289 | Error setLayerPerFrameMetadataBlobs( | 
|  | 290 | Display display, Layer layer, | 
|  | 291 | const std::vector<IComposerClient::PerFrameMetadataBlob>& metadata) override; | 
| Alec Mouri | cdf1679 | 2021-12-10 13:16:06 -0800 | [diff] [blame] | 292 | Error setDisplayBrightness(Display display, float brightness, | 
|  | 293 | const DisplayBrightnessOptions& options) override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 294 |  | 
|  | 295 | // Composer HAL 2.4 | 
| Leon Scroggins III | 5967aec | 2021-12-29 11:14:22 -0500 | [diff] [blame] | 296 | Error getDisplayCapabilities( | 
|  | 297 | Display display, | 
|  | 298 | std::vector<aidl::android::hardware::graphics::composer3::DisplayCapability>* | 
|  | 299 | outCapabilities) override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 300 | V2_4::Error getDisplayConnectionType(Display display, | 
|  | 301 | IComposerClient::DisplayConnectionType* outType) override; | 
|  | 302 | V2_4::Error getDisplayVsyncPeriod(Display display, VsyncPeriodNanos* outVsyncPeriod) override; | 
|  | 303 | V2_4::Error setActiveConfigWithConstraints( | 
|  | 304 | Display display, Config config, | 
|  | 305 | const IComposerClient::VsyncPeriodChangeConstraints& vsyncPeriodChangeConstraints, | 
|  | 306 | VsyncPeriodChangeTimeline* outTimeline) override; | 
|  | 307 | V2_4::Error setAutoLowLatencyMode(Display displayId, bool on) override; | 
|  | 308 | V2_4::Error getSupportedContentTypes( | 
|  | 309 | Display displayId, | 
|  | 310 | std::vector<IComposerClient::ContentType>* outSupportedContentTypes) override; | 
|  | 311 | V2_4::Error setContentType(Display displayId, | 
|  | 312 | IComposerClient::ContentType contentType) override; | 
|  | 313 | V2_4::Error setLayerGenericMetadata(Display display, Layer layer, const std::string& key, | 
|  | 314 | bool mandatory, const std::vector<uint8_t>& value) override; | 
|  | 315 | V2_4::Error getLayerGenericMetadataKeys( | 
|  | 316 | std::vector<IComposerClient::LayerGenericMetadataKey>* outKeys) override; | 
| Alec Mouri | cdf6cbc | 2021-11-01 17:21:15 -0700 | [diff] [blame] | 317 | Error getClientTargetProperty(Display display, | 
|  | 318 | IComposerClient::ClientTargetProperty* outClientTargetProperty, | 
|  | 319 | float* outWhitePointNits) override; | 
| Leon Scroggins III | d77d316 | 2022-01-05 10:42:28 -0500 | [diff] [blame] | 320 |  | 
|  | 321 | // AIDL Composer HAL | 
| Alec Mouri | cdf6cbc | 2021-11-01 17:21:15 -0700 | [diff] [blame] | 322 | Error setLayerWhitePointNits(Display display, Layer layer, float whitePointNits) override; | 
| Leon Scroggins III | d77d316 | 2022-01-05 10:42:28 -0500 | [diff] [blame] | 323 | Error setLayerBlockingRegion(Display display, Layer layer, | 
|  | 324 | const std::vector<IComposerClient::Rect>& blocking) override; | 
| Ady Abraham | 9fc2805 | 2021-10-14 17:21:38 -0700 | [diff] [blame] | 325 |  | 
|  | 326 | private: | 
|  | 327 | class CommandWriter : public CommandWriterBase { | 
|  | 328 | public: | 
|  | 329 | explicit CommandWriter(uint32_t initialMaxSize) : CommandWriterBase(initialMaxSize) {} | 
|  | 330 | ~CommandWriter() override {} | 
|  | 331 | }; | 
|  | 332 |  | 
|  | 333 | // Many public functions above simply write a command into the command | 
|  | 334 | // queue to batch the calls.  validateDisplay and presentDisplay will call | 
|  | 335 | // this function to execute the command queue. | 
|  | 336 | Error execute(); | 
|  | 337 |  | 
|  | 338 | sp<V2_1::IComposer> mComposer; | 
|  | 339 |  | 
|  | 340 | sp<V2_1::IComposerClient> mClient; | 
|  | 341 | sp<V2_2::IComposerClient> mClient_2_2; | 
|  | 342 | sp<V2_3::IComposerClient> mClient_2_3; | 
|  | 343 | sp<IComposerClient> mClient_2_4; | 
|  | 344 |  | 
|  | 345 | // 64KiB minus a small space for metadata such as read/write pointers | 
|  | 346 | static constexpr size_t kWriterInitialSize = 64 * 1024 / sizeof(uint32_t) - 16; | 
|  | 347 | // Max number of buffers that may be cached for a given layer | 
|  | 348 | // We obtain this number by: | 
|  | 349 | // 1. Tightly coupling this cache to the max size of BufferQueue | 
|  | 350 | // 2. Adding an additional slot for the layer caching feature in SurfaceFlinger (see: Planner.h) | 
|  | 351 | static const constexpr uint32_t kMaxLayerBufferCount = BufferQueue::NUM_BUFFER_SLOTS + 1; | 
|  | 352 | CommandWriter mWriter; | 
|  | 353 | CommandReader mReader; | 
|  | 354 | }; | 
|  | 355 |  | 
|  | 356 | } // namespace android::Hwc2 |