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Commit e9ef7c43 authored by Dominik Laskowski's avatar Dominik Laskowski
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SF: Generate stable display IDs using EDID 

The display IDs generated by HWC are opaque handles. In order for SF and
eventually DisplayManagerService to keep track of more than two displays
and recognize previously seen displays, displays should be given stable
and persistent IDs.

If the HWC supports IComposerClient.getDisplayIdentificationData, SF
parses the EDID structure to generate stable display IDs, which will
be used in a follow-up CL to replace HWC_DISPLAY_{PRIMARY,EXTERNAL}.

Bug: 74619554
Test: dumpsys SurfaceFlinger --display-identification
Test: libsurfaceflinger_unittest
Change-Id: I1a710e2efcf1581fabe48ab96a0eb4e7a5163c0c
parent 555c303a

libs/vr/libvrflinger/Android.bp

+1 −0
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ sharedLibraries = [ 
    "android.hardware.graphics.allocator@2.0",

    "android.hardware.graphics.composer@2.1",

    "android.hardware.graphics.composer@2.2",

    "android.hardware.graphics.composer@2.3",

    "libbinder",

    "libbase",

    "libbufferhubqueue",

services/surfaceflinger/Android.bp

+3 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ cc_defaults { 
        "android.hardware.graphics.allocator@2.0",

        "android.hardware.graphics.composer@2.1",

        "android.hardware.graphics.composer@2.2",

        "android.hardware.graphics.composer@2.3",

        "android.hardware.power@1.0",

        "libbase",

        "libbinder",
@@ -67,6 +68,7 @@ cc_defaults { 
        "android.hardware.graphics.allocator@2.0",

        "android.hardware.graphics.composer@2.1",

        "android.hardware.graphics.composer@2.2",

        "android.hardware.graphics.composer@2.3",

        "libhidlbase",

        "libhidltransport",

        "libhwbinder",
@@ -90,6 +92,7 @@ filegroup { 
        "ContainerLayer.cpp",

        "DisplayDevice.cpp",

        "DisplayHardware/ComposerHal.cpp",

        "DisplayHardware/DisplayIdentification.cpp",

        "DisplayHardware/FramebufferSurface.cpp",

        "DisplayHardware/HWC2.cpp",

        "DisplayHardware/HWComposer.cpp",

services/surfaceflinger/DisplayHardware/ComposerHal.cpp

+47 −15
Original line number Diff line number Diff line
@@ -22,7 +22,6 @@ 


#include "ComposerHal.h"



#include <android/hardware/graphics/composer/2.2/IComposer.h>

#include <composer-command-buffer/2.2/ComposerCommandBuffer.h>

#include <gui/BufferQueue.h>

#include <hidl/HidlTransportUtils.h>
@@ -172,22 +171,31 @@ Composer::Composer(const std::string& serviceName) 
        LOG_ALWAYS_FATAL("failed to get hwcomposer service");

    }



    mComposer->createClient(

            [&](const auto& tmpError, const auto& tmpClient)

            {

    if (sp<IComposer> composer_2_3 = IComposer::castFrom(mComposer)) {

        composer_2_3->createClient_2_3([&](const auto& tmpError, const auto& tmpClient) {

            if (tmpError == Error::NONE) {

                mClient = tmpClient;

                mClient_2_2 = tmpClient;

                mClient_2_3 = tmpClient;

            }

        });

    } else {

        mComposer->createClient([&](const auto& tmpError, const auto& tmpClient) {

            if (tmpError != Error::NONE) {

                return;

            }



            mClient = tmpClient;

            if (sp<V2_2::IComposer> composer_2_2 = V2_2::IComposer::castFrom(mComposer)) {

                mClient_2_2 = V2_2::IComposerClient::castFrom(mClient);

                LOG_ALWAYS_FATAL_IF(mClient_2_2 == nullptr,

                                    "IComposer 2.2 did not return IComposerClient 2.2");

            }

        });

    if (mClient == nullptr) {

        LOG_ALWAYS_FATAL("failed to create composer client");

    }



    // 2.2 support is optional

    sp<IComposer> composer_2_2 = IComposer::castFrom(mComposer);

    if (composer_2_2 != nullptr) {

        mClient_2_2 = IComposerClient::castFrom(mClient);

        LOG_ALWAYS_FATAL_IF(mClient_2_2 == nullptr, "IComposer 2.2 did not return IComposerClient 2.2");

    if (mClient == nullptr) {

        LOG_ALWAYS_FATAL("failed to create composer client");

    }



    if (mIsUsingVrComposer) {
@@ -957,6 +965,30 @@ Error Composer::getDataspaceSaturationMatrix(Dataspace dataspace, mat4* outMatri 
    return error;

}



// Composer HAL 2.3



Error Composer::getDisplayIdentificationData(Display display, uint8_t* outPort,

                                             std::vector<uint8_t>* outData) {

    if (!mClient_2_3) {

        return Error::UNSUPPORTED;

    }



    Error error = kDefaultError;

    mClient_2_3->getDisplayIdentificationData(display,

                                              [&](const auto& tmpError, const auto& tmpPort,

                                                  const auto& tmpData) {

                                                  error = tmpError;

                                                  if (error != Error::NONE) {

                                                      return;

                                                  }



                                                  *outPort = tmpPort;

                                                  *outData = tmpData;

                                              });



    return error;

}



CommandReader::~CommandReader()

{

    resetData();

services/surfaceflinger/DisplayHardware/ComposerHal.h

+16 −5
Original line number Diff line number Diff line
@@ -25,8 +25,8 @@ 


#include <android/frameworks/vr/composer/1.0/IVrComposerClient.h>

#include <android/hardware/graphics/common/1.1/types.h>

#include <android/hardware/graphics/composer/2.2/IComposer.h>

#include <android/hardware/graphics/composer/2.2/IComposerClient.h>

#include <android/hardware/graphics/composer/2.3/IComposer.h>

#include <android/hardware/graphics/composer/2.3/IComposerClient.h>

#include <composer-command-buffer/2.2/ComposerCommandBuffer.h>

#include <gui/HdrMetadata.h>

#include <math/mat4.h>
@@ -43,6 +43,7 @@ namespace types = hardware::graphics::common; 


namespace V2_1 = hardware::graphics::composer::V2_1;

namespace V2_2 = hardware::graphics::composer::V2_2;

namespace V2_3 = hardware::graphics::composer::V2_3;



using types::V1_0::ColorTransform;

using types::V1_0::Hdr;
@@ -61,8 +62,9 @@ using V2_1::Layer; 


using V2_2::CommandReaderBase;

using V2_2::CommandWriterBase;

using V2_2::IComposer;

using V2_2::IComposerClient;



using V2_3::IComposer;

using V2_3::IComposerClient;



using PerFrameMetadata = IComposerClient::PerFrameMetadata;

using PerFrameMetadataKey = IComposerClient::PerFrameMetadataKey;
@@ -185,6 +187,10 @@ public: 
    virtual Error getRenderIntents(Display display, ColorMode colorMode,

            std::vector<RenderIntent>* outRenderIntents) = 0;

    virtual Error getDataspaceSaturationMatrix(Dataspace dataspace, mat4* outMatrix) = 0;



    // Composer HAL 2.3

    virtual Error getDisplayIdentificationData(Display display, uint8_t* outPort,

                                               std::vector<uint8_t>* outData) = 0;

};



namespace impl {
@@ -380,6 +386,10 @@ public: 
            std::vector<RenderIntent>* outRenderIntents) override;

    Error getDataspaceSaturationMatrix(Dataspace dataspace, mat4* outMatrix) override;



    // Composer HAL 2.3

    Error getDisplayIdentificationData(Display display, uint8_t* outPort,

                                       std::vector<uint8_t>* outData) override;



private:

    class CommandWriter : public CommandWriterBase {

    public:
@@ -405,7 +415,8 @@ private: 
    sp<V2_1::IComposer> mComposer;



    sp<V2_1::IComposerClient> mClient;

    sp<IComposerClient> mClient_2_2;

    sp<V2_2::IComposerClient> mClient_2_2;

    sp<IComposerClient> mClient_2_3;



    // 64KiB minus a small space for metadata such as read/write pointers

    static constexpr size_t kWriterInitialSize =

services/surfaceflinger/DisplayHardware/DisplayIdentification.cpp

0 → 100644
+185 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2018 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */



#undef LOG_TAG

#define LOG_TAG "DisplayIdentification"



#include <algorithm>

#include <cctype>

#include <numeric>

#include <optional>



#include <log/log.h>



#include "DisplayIdentification.h"



namespace android {

namespace {



using byte_view = std::basic_string_view<uint8_t>;



constexpr size_t kEdidHeaderLength = 5;



std::optional<uint8_t> getEdidDescriptorType(const byte_view& view) {

    if (view.size() < kEdidHeaderLength || view[0] || view[1] || view[2] || view[4]) {

        return {};

    }



    return view[3];

}



std::string_view parseEdidText(const byte_view& view) {

    std::string_view text(reinterpret_cast<const char*>(view.data()), view.size());

    text = text.substr(0, text.find('\n'));



    if (!std::all_of(text.begin(), text.end(), ::isprint)) {

        ALOGW("Invalid EDID: ASCII text is not printable.");

        return {};

    }



    return text;

}



// Big-endian 16-bit value encodes three 5-bit letters where A is 0b00001.

template <size_t I>

char getPnpLetter(uint16_t id) {

    static_assert(I < 3);

    const char letter = 'A' + (static_cast<uint8_t>(id >> ((2 - I) * 5)) & 0b00011111) - 1;

    return letter < 'A' || letter > 'Z' ? '\0' : letter;

}



DisplayId getEdidDisplayId(uint8_t port, uint16_t manufacturerId, uint32_t displayNameHash) {

    return (static_cast<DisplayId>(manufacturerId) << 40) |

            (static_cast<DisplayId>(displayNameHash) << 8) | port;

}



} // namespace



bool isEdid(const DisplayIdentificationData& data) {

    const uint8_t kMagic[] = {0, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0};

    return data.size() >= sizeof(kMagic) &&

            std::equal(std::begin(kMagic), std::end(kMagic), data.begin());

}



std::optional<Edid> parseEdid(const DisplayIdentificationData& edid) {

    constexpr size_t kMinLength = 128;

    if (edid.size() < kMinLength) {

        ALOGW("Invalid EDID: structure is truncated.");

        // Attempt parsing even if EDID is malformed.

    } else {

        ALOGW_IF(edid[126] != 0, "EDID extensions are currently unsupported.");

        ALOGW_IF(std::accumulate(edid.begin(), edid.begin() + kMinLength, static_cast<uint8_t>(0)),

                 "Invalid EDID: structure does not checksum.");

    }



    constexpr size_t kManufacturerOffset = 8;

    if (edid.size() < kManufacturerOffset + sizeof(uint16_t)) {

        ALOGE("Invalid EDID: manufacturer ID is truncated.");

        return {};

    }



    // Plug and play ID encoded as big-endian 16-bit value.

    const uint16_t manufacturerId =

            (edid[kManufacturerOffset] << 8) | edid[kManufacturerOffset + 1];



    const auto pnpId = getPnpId(manufacturerId);

    if (!pnpId) {

        ALOGE("Invalid EDID: manufacturer ID is not a valid PnP ID.");

        return {};

    }



    constexpr size_t kDescriptorOffset = 54;

    if (edid.size() < kDescriptorOffset) {

        ALOGE("Invalid EDID: descriptors are missing.");

        return {};

    }



    byte_view view(edid.data(), edid.size());

    view.remove_prefix(kDescriptorOffset);



    std::string_view displayName;

    std::string_view serialNumber;

    std::string_view asciiText;



    constexpr size_t kDescriptorCount = 4;

    constexpr size_t kDescriptorLength = 18;



    for (size_t i = 0; i < kDescriptorCount; i++) {

        if (view.size() < kDescriptorLength) {

            break;

        }



        if (const auto type = getEdidDescriptorType(view)) {

            byte_view descriptor(view.data(), kDescriptorLength);

            descriptor.remove_prefix(kEdidHeaderLength);



            switch (*type) {

                case 0xfc:

                    displayName = parseEdidText(descriptor);

                    break;

                case 0xfe:

                    asciiText = parseEdidText(descriptor);

                    break;

                case 0xff:

                    serialNumber = parseEdidText(descriptor);

                    break;

            }

        }



        view.remove_prefix(kDescriptorLength);

    }



    if (displayName.empty()) {

        ALOGW("Invalid EDID: falling back to serial number due to missing display name.");

        displayName = serialNumber;

    }

    if (displayName.empty()) {

        ALOGW("Invalid EDID: falling back to ASCII text due to missing serial number.");

        displayName = asciiText;

    }

    if (displayName.empty()) {

        ALOGE("Invalid EDID: display name and fallback descriptors are missing.");

        return {};

    }



    return Edid{manufacturerId, *pnpId, displayName};

}



std::optional<PnpId> getPnpId(uint16_t manufacturerId) {

    const char a = getPnpLetter<0>(manufacturerId);

    const char b = getPnpLetter<1>(manufacturerId);

    const char c = getPnpLetter<2>(manufacturerId);

    return a && b && c ? std::make_optional(PnpId{a, b, c}) : std::nullopt;

}



std::optional<DisplayId> generateDisplayId(uint8_t port, const DisplayIdentificationData& data) {

    if (!isEdid(data)) {

        ALOGE("Display identification data has unknown format.");

        return {};

    }



    const auto edid = parseEdid(data);

    if (!edid) {

        return {};

    }



    // Hash display name instead of using product code or serial number, since the latter have been

    // observed to change on some displays with multiple inputs.

    const auto hash = static_cast<uint32_t>(std::hash<std::string_view>()(edid->displayName));

    return getEdidDisplayId(port, edid->manufacturerId, hash);

}



} // namespace android