Redesign Texture Class + Improve Presentation Engine

This commit reworks the `Texture` class to include a Vulkan Image backing that can be optionally owning or non-owning and swapped in with consideration for Vulkan image layout, it also adds CPU-sided synchronization for the texture objects with FenceCycle. It also makes the appropriate changes to `PresentationEngine` and `GraphicBufferProducer` to work with the new `Texture` class while setting the groundwork for supporting swapchain recreation. It also fixes a log in `IpcResponse` and improves the display mode selection algorithm by further weighing refresh rate.

app/CMakeLists.txt

@@ -90,8 +90,8 @@ add_library(skyline SHARED
         ${source_DIR}/skyline/gpu.cpp
         ${source_DIR}/skyline/gpu/memory_manager.cpp
         ${source_DIR}/skyline/gpu/command_scheduler.cpp
+        ${source_DIR}/skyline/gpu/texture/texture.cpp
         ${source_DIR}/skyline/gpu/presentation_engine.cpp
-        ${source_DIR}/skyline/gpu/texture.cpp
         ${source_DIR}/skyline/soc/gmmu.cpp
         ${source_DIR}/skyline/soc/host1x/syncpoint.cpp
         ${source_DIR}/skyline/soc/gm20b/gpfifo.cpp

app/src/main/cpp/skyline/common.h

@@ -21,6 +21,7 @@
 #include <sstream>
 #include <memory>
 #include <compare>
+#include <variant>
 #include <sys/mman.h>
 #include <fmt/format.h>
 #include <frozen/unordered_map.h>
@@ -444,6 +445,13 @@ namespace skyline {
     template<typename Container>
     span(const Container &) -> span<const typename Container::value_type>;
 
+    /**
+     * @brief A deduction guide for overloads required for std::visit with std::variant
+     */
+    template<class... Ts>
+    struct VariantVisitor : Ts ... { using Ts::operator()...; };
+    template<class... Ts> VariantVisitor(Ts...) -> VariantVisitor<Ts...>;
+
     /**
      * @brief A wrapper around writing logs into a log file and logcat using Android Log APIs
      */

app/src/main/cpp/skyline/gpu/presentation_engine.cpp

@@ -10,7 +10,7 @@ extern skyline::i32 Fps;
 extern skyline::i32 FrameTime;
 
 namespace skyline::gpu {
-    PresentationEngine::PresentationEngine(const DeviceState &state, const GPU &gpu) : state(state), gpu(gpu), vsyncEvent(std::make_shared<kernel::type::KEvent>(state, true)), bufferEvent(std::make_shared<kernel::type::KEvent>(state, true)), presentationTrack(static_cast<u64>(trace::TrackIds::Presentation), perfetto::ProcessTrack::Current()) {
+    PresentationEngine::PresentationEngine(const DeviceState &state, GPU &gpu) : state(state), gpu(gpu), vsyncEvent(std::make_shared<kernel::type::KEvent>(state, true)), bufferEvent(std::make_shared<kernel::type::KEvent>(state, true)), presentationTrack(static_cast<u64>(trace::TrackIds::Presentation), perfetto::ProcessTrack::Current()) {
         auto desc{presentationTrack.Serialize()};
         desc.set_name("Presentation");
         perfetto::TrackEvent::SetTrackDescriptor(presentationTrack, desc);
@@ -18,8 +18,8 @@ namespace skyline::gpu {
 
     PresentationEngine::~PresentationEngine() {
         auto env{state.jvm->GetEnv()};
-        if (!env->IsSameObject(surface, nullptr))
+        if (!env->IsSameObject(jSurface, nullptr))
-            env->DeleteGlobalRef(surface);
+            env->DeleteGlobalRef(jSurface);
     }
 
     service::hosbinder::NativeWindowTransform GetAndroidTransform(vk::SurfaceTransformFlagBitsKHR transform) {
@@ -45,22 +45,28 @@ namespace skyline::gpu {
         }
     }
 
-    void PresentationEngine::UpdateSwapchain(u16 imageCount, vk::Format imageFormat, vk::Extent2D imageExtent) {
+    void PresentationEngine::UpdateSwapchain(u16 imageCount, vk::Format imageFormat, vk::Extent2D imageExtent, bool newSurface) {
         if (!imageCount)
             return;
+        else if (imageCount > service::hosbinder::GraphicBufferProducer::MaxSlotCount)
+            throw exception("Requesting swapchain with higher image count ({}) than maximum slot count ({})", imageCount, service::hosbinder::GraphicBufferProducer::MaxSlotCount);
 
-        auto capabilities{gpu.vkPhysicalDevice.getSurfaceCapabilitiesKHR(**vkSurface)};
+        const auto &capabilities{vkSurfaceCapabilities};
         if (imageCount < capabilities.minImageCount || (capabilities.maxImageCount && imageCount > capabilities.maxImageCount))
             throw exception("Cannot update swapchain to accomodate image count: {} ({}-{})", imageCount, capabilities.minImageCount, capabilities.maxImageCount);
         if (capabilities.minImageExtent.height > imageExtent.height || capabilities.minImageExtent.width > imageExtent.width || capabilities.maxImageExtent.height < imageExtent.height || capabilities.maxImageExtent.width < imageExtent.width)
             throw exception("Cannot update swapchain to accomodate image extent: {}x{} ({}x{}-{}x{})", imageExtent.width, imageExtent.height, capabilities.minImageExtent.width, capabilities.minImageExtent.height, capabilities.maxImageExtent.width, capabilities.maxImageExtent.height);
 
+        if (swapchain.imageFormat != imageFormat || newSurface) {
+            auto formats{gpu.vkPhysicalDevice.getSurfaceFormatsKHR(**vkSurface)};
+            if (std::find(formats.begin(), formats.end(), vk::SurfaceFormatKHR{imageFormat, vk::ColorSpaceKHR::eSrgbNonlinear}) == formats.end())
+                throw exception("Surface doesn't support requested image format '{}' with colorspace '{}'", vk::to_string(imageFormat), vk::to_string(vk::ColorSpaceKHR::eSrgbNonlinear));
+        }
+
         constexpr vk::ImageUsageFlags presentUsage{vk::ImageUsageFlagBits::eColorAttachment | vk::ImageUsageFlagBits::eTransferSrc | vk::ImageUsageFlagBits::eTransferDst};
         if ((capabilities.supportedUsageFlags & presentUsage) != presentUsage)
             throw exception("Swapchain doesn't support image usage '{}': {}", vk::to_string(presentUsage), vk::to_string(capabilities.supportedUsageFlags));
 
-        transformHint = GetAndroidTransform(capabilities.currentTransform);
-
         vkSwapchain = vk::raii::SwapchainKHR(gpu.vkDevice, vk::SwapchainCreateInfoKHR{
             .surface = **vkSurface,
             .minImageCount = imageCount,
@@ -76,32 +82,56 @@ namespace skyline::gpu {
             .oldSwapchain = vkSwapchain ? **vkSwapchain : vk::SwapchainKHR{},
         });
 
-        swapchain = SwapchainContext{
+        auto vkImages{vkSwapchain->getImages()};
-            .imageCount = imageCount,
+        for (u16 slot{}; slot < imageCount; slot++) {
-            .imageFormat = imageFormat,
+            auto &vkImage{vkImages[slot]};
-            .imageExtent = imageExtent,
+            swapchain.vkImages[slot] = vkImage;
-        };
+            auto &image{swapchain.textures[slot]};
+            if (image) {
+                std::scoped_lock lock(*image);
+                image->SwapBacking(vkImage);
+                image->TransitionLayout(vk::ImageLayout::ePresentSrcKHR);
+                image->SynchronizeHost(); // Synchronize the new host backing with guest memory
+            }
+        }
+        swapchain.imageCount = imageCount;
+        swapchain.imageFormat = imageFormat;
+        swapchain.imageExtent = imageExtent;
     }
 
     void PresentationEngine::UpdateSurface(jobject newSurface) {
         std::lock_guard guard(mutex);
 
         auto env{state.jvm->GetEnv()};
-        if (!env->IsSameObject(surface, nullptr)) {
+        if (!env->IsSameObject(jSurface, nullptr)) {
-            env->DeleteGlobalRef(surface);
+            env->DeleteGlobalRef(jSurface);
-            surface = nullptr;
+            jSurface = nullptr;
         }
         if (!env->IsSameObject(newSurface, nullptr))
-            surface = env->NewGlobalRef(newSurface);
+            jSurface = env->NewGlobalRef(newSurface);
 
-        if (surface) {
+        if (vkSwapchain) {
+            for (u16 slot{}; slot < swapchain.imageCount; slot++) {
+                auto &image{swapchain.textures[slot]};
+                if (image) {
+                    std::scoped_lock lock(*image);
+                    image->SynchronizeGuest(); // Synchronize host backing to guest memory prior to being destroyed
+                    image->SwapBacking(nullptr);
+                }
+            }
+            swapchain.vkImages = {};
+            vkSwapchain.reset();
+        }
+
+        if (jSurface) {
             vkSurface.emplace(gpu.vkInstance, vk::AndroidSurfaceCreateInfoKHR{
-                .window = ANativeWindow_fromSurface(env, surface),
+                .window = ANativeWindow_fromSurface(env, jSurface),
             });
             if (!gpu.vkPhysicalDevice.getSurfaceSupportKHR(gpu.vkQueueFamilyIndex, **vkSurface))
                 throw exception("Vulkan Queue doesn't support presentation with surface");
+            vkSurfaceCapabilities = gpu.vkPhysicalDevice.getSurfaceCapabilitiesKHR(**vkSurface);
 
-            UpdateSwapchain(swapchain.imageCount, swapchain.imageFormat, swapchain.imageExtent);
+            UpdateSwapchain(swapchain.imageCount, swapchain.imageFormat, swapchain.imageExtent, true);
 
             surfaceCondition.notify_all();
         } else {
@@ -109,39 +139,42 @@ namespace skyline::gpu {
         }
     }
 
-    std::shared_ptr<Texture> PresentationEngine::CreatePresentationTexture(const std::shared_ptr<GuestTexture> &texture, u32 slot) {
+    std::shared_ptr<Texture> PresentationEngine::CreatePresentationTexture(const std::shared_ptr<GuestTexture> &texture, u8 slot) {
         std::lock_guard guard(mutex);
-        if (swapchain.imageCount <= slot)
+        if (swapchain.imageCount <= slot && slot + 1 >= vkSurfaceCapabilities.minImageCount)
-            UpdateSwapchain(std::max(slot + 1, 2U), texture->format.vkFormat, texture->dimensions);
+            UpdateSwapchain(slot + 1, texture->format.vkFormat, texture->dimensions);
-        return texture->InitializeTexture(vk::raii::Image(gpu.vkDevice, vkSwapchain->getImages().at(slot)));
+        auto host{texture->InitializeTexture(swapchain.vkImages.at(slot), vk::ImageTiling::eOptimal)};
+        swapchain.textures[slot] = host;
+        return host;
     }
 
     service::hosbinder::AndroidStatus PresentationEngine::GetFreeTexture(bool async, i32 &slot) {
         using AndroidStatus = service::hosbinder::AndroidStatus;
 
         std::unique_lock lock(mutex);
+        surfaceCondition.wait(lock, [this]() { return vkSurface.has_value(); });
         if (swapchain.dequeuedCount < swapchain.imageCount) {
-            swapchain.dequeuedCount++;
+            static vk::raii::Fence fence(gpu.vkDevice, vk::FenceCreateInfo{});
-
-            vk::raii::Fence fence(state.gpu->vkDevice, vk::FenceCreateInfo{});
             auto timeout{async ? 0ULL : std::numeric_limits<u64>::max()}; // We cannot block for a buffer to be retrieved in async mode
             auto nextImage{vkSwapchain->acquireNextImage(timeout, {}, *fence)};
-            if (nextImage.first == vk::Result::eTimeout) {
+            if (nextImage.first == vk::Result::eSuccess) {
-                return AndroidStatus::WouldBlock;
+                swapchain.dequeuedCount++;
-            } else if (nextImage.first == vk::Result::eErrorSurfaceLostKHR || nextImage.first == vk::Result::eSuboptimalKHR) {
+                while (gpu.vkDevice.waitForFences(*fence, true, std::numeric_limits<u64>::max()) == vk::Result::eTimeout);
-                surfaceCondition.wait(lock, [this]() { return vkSurface.has_value(); });
-                return GetFreeTexture(async, slot);
-            }
-
-            gpu.vkDevice.waitForFences(*fence, true, std::numeric_limits<u64>::max());
-
                 slot = nextImage.second;
                 return AndroidStatus::Ok;
+            } else if (nextImage.first == vk::Result::eNotReady || nextImage.first == vk::Result::eTimeout) {
+                return AndroidStatus::WouldBlock;
+            } else if (nextImage.first == vk::Result::eSuboptimalKHR) {
+                surfaceCondition.wait(lock, [this]() { return vkSurface.has_value(); });
+                return GetFreeTexture(async, slot);
+            } else {
+                throw exception("VkAcquireNextImageKHR returned an unhandled result '{}'", vk::to_string(nextImage.first));
+            }
         }
         return AndroidStatus::Busy;
     }
 
-    void PresentationEngine::Present(i32 slot) {
+    void PresentationEngine::Present(u32 slot) {
         std::unique_lock lock(mutex);
         surfaceCondition.wait(lock, [this]() { return vkSurface.has_value(); });
 
@@ -149,6 +182,15 @@ namespace skyline::gpu {
             throw exception("Swapchain has been presented more times than images from it have been acquired: {} (Image Count: {})", swapchain.dequeuedCount, swapchain.imageCount);
         }
 
+        {
+            std::lock_guard queueLock(gpu.queueMutex);
+            static_cast<void>(gpu.vkQueue.presentKHR(vk::PresentInfoKHR{
+                .swapchainCount = 1,
+                .pSwapchains = &**vkSwapchain,
+                .pImageIndices = &slot,
+            })); // We explicitly discard the result here as suboptimal images are expected when the game doesn't respect the transform hint
+        }
+
         vsyncEvent->Signal();
 
         if (frameTimestamp) {
@@ -167,8 +209,6 @@ namespace skyline::gpu {
     service::hosbinder::NativeWindowTransform PresentationEngine::GetTransformHint() {
         std::unique_lock lock(mutex);
         surfaceCondition.wait(lock, [this]() { return vkSurface.has_value(); });
-        if (!transformHint)
+        return GetAndroidTransform(vkSurfaceCapabilities.currentTransform);
-            transformHint = GetAndroidTransform(gpu.vkPhysicalDevice.getSurfaceCapabilitiesKHR(**vkSurface).currentTransform);
-        return *transformHint;
     }
 }

app/src/main/cpp/skyline/gpu/presentation_engine.h

@@ -5,9 +5,8 @@
 
 #include <common/trace.h>
 #include <kernel/types/KEvent.h>
-#include <services/hosbinder/native_window.h>
+#include <services/hosbinder/GraphicBufferProducer.h>
-#include <services/hosbinder/android_types.h>
+#include "texture/texture.h"
-#include "texture.h"
 
 struct ANativeWindow;
 
@@ -18,25 +17,35 @@ namespace skyline::gpu {
     class PresentationEngine {
       private:
         const DeviceState &state;
-        const GPU &gpu;
+        GPU &gpu;
+
         std::mutex mutex; //!< Synchronizes access to the surface objects
         std::condition_variable surfaceCondition; //!< Allows us to efficiently wait for Vulkan surface to be initialized
-        jobject surface{}; //!< The Surface object backing the ANativeWindow
+        jobject jSurface{}; //!< The Java Surface object backing the ANativeWindow
 
         std::optional<vk::raii::SurfaceKHR> vkSurface; //!< The Vulkan Surface object that is backed by ANativeWindow
-        std::optional<service::hosbinder::NativeWindowTransform> transformHint; //!< The optimal transform for the application to render as
+        vk::SurfaceCapabilitiesKHR vkSurfaceCapabilities; //!< The capabilities of the current Vulkan Surface
+
         std::optional<vk::raii::SwapchainKHR> vkSwapchain; //!< The Vulkan swapchain and the properties associated with it
         struct SwapchainContext {
-            u16 imageCount{};
+            std::array<std::shared_ptr<Texture>, service::hosbinder::GraphicBufferProducer::MaxSlotCount> textures{};
-            i32 dequeuedCount{};
+            std::array<VkImage, service::hosbinder::GraphicBufferProducer::MaxSlotCount> vkImages{VK_NULL_HANDLE};
+            u8 imageCount{};
+            i8 dequeuedCount{};
             vk::Format imageFormat{};
             vk::Extent2D imageExtent{};
+
+            static_assert(std::numeric_limits<decltype(imageCount)>::max() >= service::hosbinder::GraphicBufferProducer::MaxSlotCount);
+            static_assert(std::numeric_limits<decltype(dequeuedCount)>::max() >= service::hosbinder::GraphicBufferProducer::MaxSlotCount);
         } swapchain; //!< The properties of the currently created swapchain
 
         u64 frameTimestamp{}; //!< The timestamp of the last frame being shown
         perfetto::Track presentationTrack; //!< Perfetto track used for presentation events
 
-        void UpdateSwapchain(u16 imageCount, vk::Format imageFormat, vk::Extent2D imageExtent);
+        /**
+         * @note 'PresentationEngine::mutex' **must** be locked prior to calling this
+         */
+        void UpdateSwapchain(u16 imageCount, vk::Format imageFormat, vk::Extent2D imageExtent, bool newSurface = false);
 
       public:
         texture::Dimensions resolution{};
@@ -44,7 +53,7 @@ namespace skyline::gpu {
         std::shared_ptr<kernel::type::KEvent> vsyncEvent; //!< Signalled every time a frame is drawn
         std::shared_ptr<kernel::type::KEvent> bufferEvent; //!< Signalled every time a buffer is freed
 
-        PresentationEngine(const DeviceState &state, const GPU& gpu);
+        PresentationEngine(const DeviceState &state, GPU &gpu);
 
         ~PresentationEngine();
 
@@ -56,18 +65,18 @@ namespace skyline::gpu {
         /**
          * @brief Creates a Texture object from a GuestTexture as a part of the Vulkan swapchain
          */
-        std::shared_ptr<Texture> CreatePresentationTexture(const std::shared_ptr<GuestTexture> &texture, u32 slot);
+        std::shared_ptr<Texture> CreatePresentationTexture(const std::shared_ptr<GuestTexture> &texture, u8 slot);
 
         /**
          * @param async If to return immediately when a texture is not available
          * @param slot The slot the freed texture is in is written into this, it is untouched if there's an error
          */
-        service::hosbinder::AndroidStatus GetFreeTexture(bool async, i32& slot);
+        service::hosbinder::AndroidStatus GetFreeTexture(bool async, i32 &slot);
 
         /**
          * @brief Send a texture from a slot to the presentation queue to be displayed
          */
-        void Present(i32 slot);
+        void Present(u32 slot);
 
         /**
          * @return A transform that the application should render with to elide costly transforms later

app/src/main/cpp/skyline/gpu/texture.cpp

@@ -1,88 +0,0 @@
-// SPDX-License-Identifier: MPL-2.0
-// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
-
-#include <gpu.h>
-#include <common/trace.h>
-#include <kernel/types/KProcess.h>
-#include "texture.h"
-
-namespace skyline::gpu {
-    GuestTexture::GuestTexture(const DeviceState &state, u8 *pointer, texture::Dimensions dimensions, texture::Format format, texture::TileMode tiling, texture::TileConfig layout) : state(state), pointer(pointer), dimensions(dimensions), format(format), tileMode(tiling), tileConfig(layout) {}
-
-    std::shared_ptr<Texture> GuestTexture::InitializeTexture(vk::raii::Image &&backing, std::optional<texture::Format> pFormat, std::optional<texture::Dimensions> pDimensions, texture::Swizzle swizzle) {
-        if (!host.expired())
-            throw exception("Trying to create multiple Texture objects from a single GuestTexture");
-        auto sharedHost{std::make_shared<Texture>(std::move(backing), shared_from_this(), pDimensions ? *pDimensions : dimensions, pFormat ? *pFormat : format, swizzle)};
-        host = sharedHost;
-        return sharedHost;
-    }
-
-    Texture::Texture(vk::raii::Image&& backing, std::shared_ptr<GuestTexture> guest, texture::Dimensions dimensions, texture::Format format, texture::Swizzle swizzle) : backing(std::move(backing)), guest(std::move(guest)), dimensions(dimensions), format(format), swizzle(swizzle) {
-        SynchronizeHost();
-    }
-
-    void Texture::SynchronizeHost() {
-        TRACE_EVENT("gpu", "Texture::SynchronizeHost");
-        auto pointer{guest->pointer};
-        auto size{format.GetSize(dimensions)};
-        u8* output{nullptr};
-        return;
-
-        if (guest->tileMode == texture::TileMode::Block) {
-            // Reference on Block-linear tiling: https://gist.github.com/PixelyIon/d9c35050af0ef5690566ca9f0965bc32
-            constexpr u8 sectorWidth{16}; // The width of a sector in bytes
-            constexpr u8 sectorHeight{2}; // The height of a sector in lines
-            constexpr u8 gobWidth{64}; // The width of a GOB in bytes
-            constexpr u8 gobHeight{8}; // The height of a GOB in lines
-
-            auto blockHeight{guest->tileConfig.blockHeight}; // The height of the blocks in GOBs
-            auto robHeight{gobHeight * blockHeight}; // The height of a single ROB (Row of Blocks) in lines
-            auto surfaceHeight{dimensions.height / format.blockHeight}; // The height of the surface in lines
-            auto surfaceHeightRobs{util::AlignUp(surfaceHeight, robHeight) / robHeight}; // The height of the surface in ROBs (Row Of Blocks)
-            auto robWidthBytes{util::AlignUp((guest->tileConfig.surfaceWidth / format.blockWidth) * format.bpb, gobWidth)}; // The width of a ROB in bytes
-            auto robWidthBlocks{robWidthBytes / gobWidth}; // The width of a ROB in blocks (and GOBs because block width == 1 on the Tegra X1)
-            auto robBytes{robWidthBytes * robHeight}; // The size of a ROB in bytes
-            auto gobYOffset{robWidthBytes * gobHeight}; // The offset of the next Y-axis GOB from the current one in linear space
-
-            auto inputSector{pointer}; // The address of the input sector
-            auto outputRob{output}; // The address of the output block
-
-            for (u32 rob{}, y{}, paddingY{}; rob < surfaceHeightRobs; rob++) { // Every Surface contains `surfaceHeightRobs` ROBs
-                auto outputBlock{outputRob}; // We iterate through a block independently of the ROB
-                for (u32 block{}; block < robWidthBlocks; block++) { // Every ROB contains `surfaceWidthBlocks` Blocks
-                    auto outputGob{outputBlock}; // We iterate through a GOB independently of the block
-                    for (u32 gobY{}; gobY < blockHeight; gobY++) { // Every Block contains `blockHeight` Y-axis GOBs
-                        for (u32 index{}; index < sectorWidth * sectorHeight; index++) { // Every Y-axis GOB contains `sectorWidth * sectorHeight` sectors
-                            u32 xT{((index << 3) & 0b10000) | ((index << 1) & 0b100000)}; // Morton-Swizzle on the X-axis
-                            u32 yT{((index >> 1) & 0b110) | (index & 0b1)}; // Morton-Swizzle on the Y-axis
-                            std::memcpy(outputGob + (yT * robWidthBytes) + xT, inputSector, sectorWidth);
-                            inputSector += sectorWidth; // `sectorWidth` bytes are of sequential image data
-                        }
-                        outputGob += gobYOffset; // Increment the output GOB to the next Y-axis GOB
-                    }
-                    inputSector += paddingY; // Increment the input sector to the next sector
-                    outputBlock += gobWidth; // Increment the output block to the next block (As Block Width = 1 GOB Width)
-                }
-                outputRob += robBytes; // Increment the output block to the next ROB
-
-                y += robHeight; // Increment the Y position to the next ROB
-                blockHeight = static_cast<u8>(std::min(static_cast<u32>(blockHeight), (surfaceHeight - y) / gobHeight)); // Calculate the amount of Y GOBs which aren't padding
-                paddingY = (guest->tileConfig.blockHeight - blockHeight) * (sectorWidth * sectorWidth * sectorHeight); // Calculate the amount of padding between contiguous sectors
-            }
-        } else if (guest->tileMode == texture::TileMode::Pitch) {
-            auto sizeLine{guest->format.GetSize(dimensions.width, 1)}; // The size of a single line of pixel data
-            auto sizeStride{guest->format.GetSize(guest->tileConfig.pitch, 1)}; // The size of a single stride of pixel data
-
-            auto inputLine{pointer}; // The address of the input line
-            auto outputLine{output}; // The address of the output line
-
-            for (u32 line{}; line < dimensions.height; line++) {
-                std::memcpy(outputLine, inputLine, sizeLine);
-                inputLine += sizeStride;
-                outputLine += sizeLine;
-            }
-        } else if (guest->tileMode == texture::TileMode::Linear) {
-            std::memcpy(output, pointer, size);
-        }
-    }
-}

app/src/main/cpp/skyline/gpu/texture/texture.cpp

@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: MPL-2.0
+// Copyright © 2020 Skyline Team and Contributors (https://github.com/skyline-emu/)
+
+#include <gpu.h>
+#include <common/trace.h>
+#include <kernel/types/KProcess.h>
+#include "texture.h"
+
+namespace skyline::gpu {
+    GuestTexture::GuestTexture(const DeviceState &state, u8 *pointer, texture::Dimensions dimensions, texture::Format format, texture::TileMode tiling, texture::TileConfig layout) : state(state), pointer(pointer), dimensions(dimensions), format(format), tileMode(tiling), tileConfig(layout) {}
+
+    std::shared_ptr<Texture> GuestTexture::InitializeTexture(vk::Image backing, std::optional<vk::ImageTiling> tiling, vk::ImageLayout pLayout, std::optional<texture::Format> pFormat, std::optional<texture::Dimensions> pDimensions, texture::Swizzle swizzle) {
+        if (!host.expired())
+            throw exception("Trying to create multiple Texture objects from a single GuestTexture");
+        auto sharedHost{std::make_shared<Texture>(*state.gpu, backing, pLayout, shared_from_this(), pDimensions ? *pDimensions : dimensions, pFormat ? *pFormat : format, tiling ? *tiling : (tileMode == texture::TileMode::Block) ? vk::ImageTiling::eOptimal : vk::ImageTiling::eLinear, swizzle)};
+        host = sharedHost;
+        return sharedHost;
+    }
+
+    std::shared_ptr<Texture> GuestTexture::InitializeTexture(vk::raii::Image &&backing, std::optional<vk::ImageTiling> tiling, vk::ImageLayout pLayout, std::optional<texture::Format> pFormat, std::optional<texture::Dimensions> pDimensions, texture::Swizzle swizzle) {
+        if (!host.expired())
+            throw exception("Trying to create multiple Texture objects from a single GuestTexture");
+        auto sharedHost{std::make_shared<Texture>(*state.gpu, std::move(backing), pLayout, shared_from_this(), pDimensions ? *pDimensions : dimensions, pFormat ? *pFormat : format, tiling ? *tiling : (tileMode == texture::TileMode::Block) ? vk::ImageTiling::eOptimal : vk::ImageTiling::eLinear, swizzle)};
+        host = sharedHost;
+        return sharedHost;
+    }
+
+    Texture::Texture(GPU &gpu, BackingType &&backing, vk::ImageLayout layout, std::shared_ptr<GuestTexture> guest, texture::Dimensions dimensions, texture::Format format, vk::ImageTiling tiling, vk::ComponentMapping mapping) : gpu(gpu), backing(std::move(backing)), layout(layout), guest(std::move(guest)), dimensions(dimensions), format(format), tiling(tiling), mapping(mapping) {
+        if (GetBacking())
+            SynchronizeHost();
+    }
+
+    bool Texture::WaitOnBacking() {
+        if (GetBacking()) [[likely]] {
+            return false;
+        } else {
+            std::unique_lock lock(mutex, std::adopt_lock);
+            backingCondition.wait(lock, [&]() -> bool { return GetBacking(); });
+            lock.release();
+            return true;
+        }
+    }
+
+    void Texture::WaitOnFence() {
+        if (cycle) {
+            cycle->Wait();
+            cycle.reset();
+        }
+    }
+
+    void Texture::SwapBacking(BackingType &&pBacking, vk::ImageLayout pLayout) {
+        WaitOnFence();
+
+        backing = std::move(pBacking);
+        layout = pLayout;
+        if (GetBacking())
+            backingCondition.notify_all();
+    }
+
+    void Texture::TransitionLayout(vk::ImageLayout pLayout) {
+        WaitOnBacking();
+        WaitOnFence();
+
+        if (layout != pLayout) {
+            cycle = gpu.scheduler.Submit([&](vk::raii::CommandBuffer &commandBuffer) {
+                commandBuffer.pipelineBarrier(layout != vk::ImageLayout::eUndefined ? vk::PipelineStageFlagBits::eTopOfPipe : vk::PipelineStageFlagBits::eBottomOfPipe, vk::PipelineStageFlagBits::eBottomOfPipe, {}, {}, {}, vk::ImageMemoryBarrier{
+                    .image = GetBacking(),
+                    .srcAccessMask = vk::AccessFlagBits::eMemoryWrite,
+                    .dstAccessMask = vk::AccessFlagBits::eMemoryRead,
+                    .oldLayout = layout,
+                    .newLayout = pLayout,
+                    .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .subresourceRange = {
+                        .aspectMask = vk::ImageAspectFlagBits::eColor,
+                        .levelCount = 1,
+                        .layerCount = 1,
+                    },
+                });
+            });
+            layout = pLayout;
+        }
+    }
+
+    void Texture::SynchronizeHost() {
+        TRACE_EVENT("gpu", "Texture::SynchronizeHost");
+        auto pointer{guest->pointer};
+        auto size{format.GetSize(dimensions)};
+
+        auto stagingBuffer{[&]() {
+            if (tiling == vk::ImageTiling::eOptimal) {
+                return gpu.memory.AllocateStagingBuffer(size);
+            } else {
+                throw exception("Guest -> Host synchronization of images tiled as '{}' isn't implemented", vk::to_string(tiling));
+            }
+        }()};
+
+        if (guest->tileMode == texture::TileMode::Block) {
+            // Reference on Block-linear tiling: https://gist.github.com/PixelyIon/d9c35050af0ef5690566ca9f0965bc32
+            constexpr u8 sectorWidth{16}; // The width of a sector in bytes
+            constexpr u8 sectorHeight{2}; // The height of a sector in lines
+            constexpr u8 gobWidth{64}; // The width of a GOB in bytes
+            constexpr u8 gobHeight{8}; // The height of a GOB in lines
+
+            auto blockHeight{guest->tileConfig.blockHeight}; // The height of the blocks in GOBs
+            auto robHeight{gobHeight * blockHeight}; // The height of a single ROB (Row of Blocks) in lines
+            auto surfaceHeight{dimensions.height / guest->format.blockHeight}; // The height of the surface in lines
+            auto surfaceHeightRobs{util::AlignUp(surfaceHeight, robHeight) / robHeight}; // The height of the surface in ROBs (Row Of Blocks)
+            auto robWidthBytes{util::AlignUp((guest->tileConfig.surfaceWidth / guest->format.blockWidth) * guest->format.bpb, gobWidth)}; // The width of a ROB in bytes
+            auto robWidthBlocks{robWidthBytes / gobWidth}; // The width of a ROB in blocks (and GOBs because block width == 1 on the Tegra X1)
+            auto robBytes{robWidthBytes * robHeight}; // The size of a ROB in bytes
+            auto gobYOffset{robWidthBytes * gobHeight}; // The offset of the next Y-axis GOB from the current one in linear space
+
+            auto inputSector{pointer}; // The address of the input sector
+            auto outputRob{stagingBuffer->data()}; // The address of the output block
+
+            for (u32 rob{}, y{}, paddingY{}; rob < surfaceHeightRobs; rob++) { // Every Surface contains `surfaceHeightRobs` ROBs
+                auto outputBlock{outputRob}; // We iterate through a block independently of the ROB
+                for (u32 block{}; block < robWidthBlocks; block++) { // Every ROB contains `surfaceWidthBlocks` Blocks
+                    auto outputGob{outputBlock}; // We iterate through a GOB independently of the block
+                    for (u32 gobY{}; gobY < blockHeight; gobY++) { // Every Block contains `blockHeight` Y-axis GOBs
+                        for (u32 index{}; index < sectorWidth * sectorHeight; index++) { // Every Y-axis GOB contains `sectorWidth * sectorHeight` sectors
+                            u32 xT{((index << 3) & 0b10000) | ((index << 1) & 0b100000)}; // Morton-Swizzle on the X-axis
+                            u32 yT{((index >> 1) & 0b110) | (index & 0b1)}; // Morton-Swizzle on the Y-axis
+                            std::memcpy(outputGob + (yT * robWidthBytes) + xT, inputSector, sectorWidth);
+                            inputSector += sectorWidth; // `sectorWidth` bytes are of sequential image data
+                        }
+                        outputGob += gobYOffset; // Increment the output GOB to the next Y-axis GOB
+                    }
+                    inputSector += paddingY; // Increment the input sector to the next sector
+                    outputBlock += gobWidth; // Increment the output block to the next block (As Block Width = 1 GOB Width)
+                }
+                outputRob += robBytes; // Increment the output block to the next ROB
+
+                y += robHeight; // Increment the Y position to the next ROB
+                blockHeight = static_cast<u8>(std::min(static_cast<u32>(blockHeight), (surfaceHeight - y) / gobHeight)); // Calculate the amount of Y GOBs which aren't padding
+                paddingY = (guest->tileConfig.blockHeight - blockHeight) * (sectorWidth * sectorWidth * sectorHeight); // Calculate the amount of padding between contiguous sectors
+            }
+        } else if (guest->tileMode == texture::TileMode::Pitch) {
+            auto sizeLine{guest->format.GetSize(dimensions.width, 1)}; // The size of a single line of pixel data
+            auto sizeStride{guest->format.GetSize(guest->tileConfig.pitch, 1)}; // The size of a single stride of pixel data
+
+            auto inputLine{pointer}; // The address of the input line
+            auto outputLine{stagingBuffer->data()}; // The address of the output line
+
+            for (u32 line{}; line < dimensions.height; line++) {
+                std::memcpy(outputLine, inputLine, sizeLine);
+                inputLine += sizeStride;
+                outputLine += sizeLine;
+            }
+        } else if (guest->tileMode == texture::TileMode::Linear) {
+            std::memcpy(stagingBuffer->data(), pointer, size);
+        }
+
+        if (WaitOnBacking() && size != format.GetSize(dimensions))
+            throw exception("Backing properties changing during sync is not supported");
+        WaitOnFence();
+
+        cycle = gpu.scheduler.Submit([&](vk::raii::CommandBuffer &commandBuffer) {
+            auto image{GetBacking()};
+            if (layout != vk::ImageLayout::eTransferDstOptimal) {
+                commandBuffer.pipelineBarrier(layout != vk::ImageLayout::eUndefined ? vk::PipelineStageFlagBits::eTopOfPipe : vk::PipelineStageFlagBits::eBottomOfPipe, vk::PipelineStageFlagBits::eTransfer, {}, {}, {}, vk::ImageMemoryBarrier{
+                    .image = image,
+                    .srcAccessMask = vk::AccessFlagBits::eMemoryRead | vk::AccessFlagBits::eMemoryWrite,
+                    .dstAccessMask = vk::AccessFlagBits::eTransferWrite,
+                    .oldLayout = layout,
+                    .newLayout = vk::ImageLayout::eTransferDstOptimal,
+                    .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .subresourceRange = {
+                        .aspectMask = vk::ImageAspectFlagBits::eColor,
+                        .levelCount = 1,
+                        .layerCount = 1,
+                    },
+                });
+
+                if (layout == vk::ImageLayout::eUndefined)
+                    layout = vk::ImageLayout::eTransferDstOptimal;
+            }
+
+            commandBuffer.copyBufferToImage(stagingBuffer->vkBuffer, image, vk::ImageLayout::eTransferDstOptimal, vk::BufferImageCopy{
+                .imageExtent = dimensions,
+                .imageSubresource = {
+                    .aspectMask = vk::ImageAspectFlagBits::eColor,
+                    .layerCount = 1,
+                },
+            });
+
+            if (layout != vk::ImageLayout::eTransferDstOptimal)
+                commandBuffer.pipelineBarrier(vk::PipelineStageFlagBits::eTransfer, vk::PipelineStageFlagBits::eTransfer, {}, {}, {}, vk::ImageMemoryBarrier{
+                    .image = image,
+                    .srcAccessMask = vk::AccessFlagBits::eTransferWrite,
+                    .dstAccessMask = vk::AccessFlagBits::eMemoryRead,
+                    .oldLayout = vk::ImageLayout::eTransferDstOptimal,
+                    .newLayout = layout,
+                    .srcQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .dstQueueFamilyIndex = VK_QUEUE_FAMILY_IGNORED,
+                    .subresourceRange = {
+                        .aspectMask = vk::ImageAspectFlagBits::eColor,
+                        .levelCount = 1,
+                        .layerCount = 1,
+                    },
+                });
+        });
+
+        cycle->AttachObject(stagingBuffer);
+    }
+
+    void Texture::SynchronizeGuest() {
+        WaitOnBacking();
+        WaitOnFence();
+
+        TRACE_EVENT("gpu", "Texture::SynchronizeGuest");
+        // TODO: Write Host -> Guest Synchronization
+    }
+}

app/src/main/cpp/skyline/gpu/texture/texture.h

@@ -3,8 +3,7 @@
 
 #pragma once
 
-#include <common.h>
+#include <gpu/fence_cycle.h>
-#include <vulkan/vulkan_raii.hpp>
 
 namespace skyline::gpu {
     namespace texture {
@@ -111,7 +110,7 @@ namespace skyline::gpu {
             u32 pitch; //!< The pitch of the texture if it's pitch linear
         };
 
-        enum class SwizzleChannel {
+        enum class SwizzleChannel : u8 {
             Zero, //!< Write 0 to the channel
             One, //!< Write 1 to the channel
             Red, //!< Red color channel
@@ -125,6 +124,32 @@ namespace skyline::gpu {
             SwizzleChannel green{SwizzleChannel::Green}; //!< Swizzle for the green channel
             SwizzleChannel blue{SwizzleChannel::Blue}; //!< Swizzle for the blue channel
             SwizzleChannel alpha{SwizzleChannel::Alpha}; //!< Swizzle for the alpha channel
+
+            constexpr operator vk::ComponentMapping() {
+                auto swizzleConvert{[](SwizzleChannel channel) {
+                    switch (channel) {
+                        case SwizzleChannel::Zero:
+                            return vk::ComponentSwizzle::eZero;
+                        case SwizzleChannel::One:
+                            return vk::ComponentSwizzle::eOne;
+                        case SwizzleChannel::Red:
+                            return vk::ComponentSwizzle::eR;
+                        case SwizzleChannel::Green:
+                            return vk::ComponentSwizzle::eG;
+                        case SwizzleChannel::Blue:
+                            return vk::ComponentSwizzle::eB;
+                        case SwizzleChannel::Alpha:
+                            return vk::ComponentSwizzle::eA;
+                    }
+                }};
+
+                return vk::ComponentMapping{
+                    .r = swizzleConvert(red),
+                    .g = swizzleConvert(green),
+                    .b = swizzleConvert(blue),
+                    .a = swizzleConvert(alpha),
+                };
+            }
         };
     }
 
@@ -154,29 +179,101 @@ namespace skyline::gpu {
 
         /**
          * @brief Creates a corresponding host texture object for this guest texture
-         * @param backing The Vulkan Image that is used as the backing on the host
+         * @param backing The Vulkan Image that is used as the backing on the host, its lifetime is not managed by the host texture object
+         * @param tiling The tiling used by the image on host, this is the same as guest by default
+         * @param layout The initial layout of the Vulkan Image, this is used for efficient layout management
          * @param format The format of the host texture (Defaults to the format of the guest texture)
          * @param dimensions The dimensions of the host texture (Defaults to the dimensions of the host texture)
          * @param swizzle The channel swizzle of the host texture (Defaults to no channel swizzling)
          * @return A shared pointer to the host texture object
          * @note There can only be one host texture for a corresponding guest texture
          */
-        std::shared_ptr<Texture> InitializeTexture(vk::raii::Image &&backing, std::optional<texture::Format> format = std::nullopt, std::optional<texture::Dimensions> dimensions = std::nullopt, texture::Swizzle swizzle = {});
+        std::shared_ptr<Texture> InitializeTexture(vk::Image backing, std::optional<vk::ImageTiling> tiling = std::nullopt, vk::ImageLayout layout = vk::ImageLayout::eUndefined, std::optional<texture::Format> format = std::nullopt, std::optional<texture::Dimensions> dimensions = std::nullopt, texture::Swizzle swizzle = {});
+
+        /**
+         * @note As a RAII object is used here, the lifetime of the backing is handled by the host texture
+         */
+        std::shared_ptr<Texture> InitializeTexture(vk::raii::Image &&backing, std::optional<vk::ImageTiling> tiling = std::nullopt, vk::ImageLayout layout = vk::ImageLayout::eUndefined, std::optional<texture::Format> format = std::nullopt, std::optional<texture::Dimensions> dimensions = std::nullopt, texture::Swizzle swizzle = {});
     };
 
     /**
      * @brief A texture which is backed by host constructs while being synchronized with the underlying guest texture
+     * @note This class conforms to the Lockable and BasicLockable C++ named requirements
      */
     class Texture {
-      public:
+      private:
-        vk::raii::Image backing; //!< The object that holds a host copy of the guest texture
+        GPU &gpu;
-        std::shared_ptr<GuestTexture> guest; //!< The guest texture from which this was created, it's required for syncing
+        std::mutex mutex; //!< Synchronizes any mutations to the texture or its backing
-        texture::Dimensions dimensions;
+        std::condition_variable backingCondition; //!< Signalled when a valid backing has been swapped in
-        texture::Format format;
+        using BackingType = std::variant<vk::Image, vk::raii::Image>;
-        texture::Swizzle swizzle;
+        BackingType backing; //!< The Vulkan image that backs this texture, it is nullable
+        std::shared_ptr<FenceCycle> cycle; //!< A fence cycle for when any host operation mutating the texture has completed, it must be waited on prior to any mutations to the backing
+        vk::ImageLayout layout;
+
+        /**
+         * @note The handle returned is nullable and the appropriate precautions should be taken
+         */
+        constexpr vk::Image GetBacking() {
+            return std::visit(VariantVisitor{
+                [](vk::Image image) { return image; },
+                [](const vk::raii::Image &image) { return *image; },
+            }, backing);
+        }
 
       public:
-        Texture(vk::raii::Image &&backing, std::shared_ptr<GuestTexture> guest, texture::Dimensions dimensions, texture::Format format, texture::Swizzle swizzle);
+        std::shared_ptr<GuestTexture> guest; //!< The guest texture from which this was created, it's required for syncing and not nullable
+        texture::Dimensions dimensions;
+        texture::Format format;
+        vk::ImageTiling tiling;
+        vk::ComponentMapping mapping;
+
+        Texture(GPU &gpu, BackingType &&backing, vk::ImageLayout layout, std::shared_ptr<GuestTexture> guest, texture::Dimensions dimensions, texture::Format format, vk::ImageTiling tiling, vk::ComponentMapping mapping);
+
+        /**
+         * @brief Acquires an exclusive lock on the texture for the calling thread
+         */
+        void lock() {
+            mutex.lock();
+        }
+
+        /**
+         * @brief Relinquishes an existing lock on the texture by the calling thread
+         */
+        void unlock() {
+            mutex.unlock();
+        }
+
+        /**
+         * @brief Attempts to acquire an exclusive lock but returns immediately if it's captured by another thread
+         */
+        bool try_lock() {
+            return mutex.try_lock();
+        }
+
+        /**
+         * @brief Waits on the texture backing to be a valid non-null Vulkan image
+         * @return If the mutex could be unlocked during the function
+         * @note The texture **must** be locked prior to calling this
+         */
+        bool WaitOnBacking();
+
+        /**
+         * @brief Waits on a fence cycle if it exists till it's signalled and resets it after
+         * @note The texture **must** be locked prior to calling this
+         */
+        void WaitOnFence();
+
+        /**
+         * @note All memory residing in the current backing is not copied to the new backing, it must be handled externally
+         * @note The texture **must** be locked prior to calling this
+         */
+        void SwapBacking(BackingType &&backing, vk::ImageLayout layout = vk::ImageLayout::eUndefined);
+
+        /**
+         * @brief Transitions the backing to the supplied layout, if the backing already is in this layout then this does nothing
+         * @note The texture **must** be locked prior to calling this
+         */
+        void TransitionLayout(vk::ImageLayout layout);
 
         /**
          * @brief Convert this texture to the specified tiling mode
@@ -202,11 +299,13 @@ namespace skyline::gpu {
 
         /**
          * @brief Synchronizes the host texture with the guest after it has been modified
+         * @note The texture **must** be locked prior to calling this
          */
         void SynchronizeHost();
 
         /**
          * @brief Synchronizes the guest texture with the host texture after it has been modified
+         * @note The texture **must** be locked prior to calling this
          */
         void SynchronizeGuest();
     };

app/src/main/cpp/skyline/kernel/ipc.cpp

@@ -183,6 +183,6 @@ namespace skyline::kernel::ipc {
             }
         }
 
-        state.logger->Verbose("Output: Raw Size: {}, Command ID: 0x{:X}, Copy Handles: {}, Move Handles: {}", static_cast<u32>(header->rawSize), static_cast<u32>(payloadHeader->value), copyHandles.size(), moveHandles.size());
+        state.logger->Verbose("Output: Raw Size: {}, Result: 0x{:X}, Copy Handles: {}, Move Handles: {}", static_cast<u32>(header->rawSize), static_cast<u32>(payloadHeader->value), copyHandles.size(), moveHandles.size());
     }
 }

app/src/main/cpp/skyline/services/hosbinder/GraphicBufferProducer.cpp

@@ -5,7 +5,7 @@
 
 #include <android/hardware_buffer.h>
 #include <gpu.h>
-#include <gpu/format.h>
+#include <gpu/texture/format.h>
 #include <soc.h>
 #include <common/settings.h>
 #include <services/nvdrv/driver.h>
@@ -137,9 +137,14 @@ namespace skyline::service::hosbinder {
             throw exception("Any non-identity sticky transform is not supported: '{}' ({:#b})", ToString(stickyTransform), static_cast<u32>(stickyTransform));
 
         fence.Wait(state.soc->host1x);
+
+        {
+            std::scoped_lock textureLock(*buffer.texture);
             buffer.texture->SynchronizeHost();
+            buffer.texture->WaitOnFence();
             state.gpu->presentation.Present(slot);
             state.gpu->presentation.bufferEvent->Signal();
+        }
 
         width = defaultWidth;
         height = defaultHeight;
@@ -345,14 +350,14 @@ namespace skyline::service::hosbinder {
 
         gpu::texture::TileMode tileMode;
         gpu::texture::TileConfig tileConfig;
-        if (surface.layout != NvSurfaceLayout::Blocklinear) {
+        if (surface.layout == NvSurfaceLayout::Blocklinear) {
             tileMode = gpu::texture::TileMode::Block;
             tileConfig = {
                 .surfaceWidth = static_cast<u16>(surface.width),
                 .blockHeight = static_cast<u8>(1U << surface.blockHeightLog2),
                 .blockDepth = 1,
             };
-        } else if (surface.layout != NvSurfaceLayout::Pitch) {
+        } else if (surface.layout == NvSurfaceLayout::Pitch) {
             tileMode = gpu::texture::TileMode::Pitch;
             tileConfig = {
                 .pitch = surface.pitch,
@@ -408,12 +413,13 @@ namespace skyline::service::hosbinder {
                 auto queueBufferInputSize{in.Pop<u64>()};
                 if (queueBufferInputSize != QueueBufferInputSize)
                     throw exception("The size of QueueBufferInput in the Parcel (0x{:X}) doesn't match the expected size (0x{:X})", queueBufferInputSize, QueueBufferInputSize);
-                QueueBuffer(slot, in.Pop<i64>(), in.Pop<u32>(), in.Pop<AndroidRect>(), in.Pop<NativeWindowScalingMode>(), in.Pop<NativeWindowTransform>(), in.Pop<NativeWindowTransform>(), in.Pop<u32>(), in.Pop<u32>(), in.Pop<AndroidFence>(), width, height, transformHint, pendingBufferCount);
+                auto result{QueueBuffer(slot, in.Pop<i64>(), in.Pop<u32>(), in.Pop<AndroidRect>(), in.Pop<NativeWindowScalingMode>(), in.Pop<NativeWindowTransform>(), in.Pop<NativeWindowTransform>(), in.Pop<u32>(), in.Pop<u32>(), in.Pop<AndroidFence>(), width, height, transformHint, pendingBufferCount)};
 
                 out.Push(width);
                 out.Push(height);
                 out.Push(transformHint);
                 out.Push(pendingBufferCount);
+                out.Push(result);
                 break;
             }
 

app/src/main/cpp/skyline/services/hosbinder/GraphicBufferProducer.h

@@ -80,10 +80,12 @@ namespace skyline::service::hosbinder {
      * @url https://cs.android.com/android/platform/superproject/+/android-5.1.1_r38:frameworks/native/libs/gui/BufferQueueCore.cpp
      */
     class GraphicBufferProducer {
+      public:
+        constexpr static u8 MaxSlotCount{16}; //!< The maximum amount of buffer slots that a buffer queue can hold, Android supports 64 but they go unused for applications like games so we've lowered this to 16 (https://cs.android.com/android/platform/superproject/+/android-5.1.1_r38:frameworks/native/include/gui/BufferQueueDefs.h;l=29)
+
       private:
         const DeviceState &state;
         std::mutex mutex; //!< Synchronizes access to the buffer queue
-        constexpr static u8 MaxSlotCount{16}; //!< The maximum amount of buffer slots that a buffer queue can hold, Android supports 64 but they go unused for applications like games so we've lowered this to 16
         std::array<BufferSlot, MaxSlotCount> queue;
         u8 activeSlotCount{2}; //!< The amount of slots in the queue that can be used
         u8 hasBufferCount{}; //!< The amount of slots with buffers attached in the queue

app/src/main/java/emu/skyline/EmulationActivity.kt

@@ -212,7 +212,7 @@ class EmulationActivity : AppCompatActivity(), SurfaceHolder.Callback, View.OnTo
         }
 
         @Suppress("DEPRECATION") val display = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) display!! else windowManager.defaultDisplay
-        display?.supportedModes?.maxByOrNull { it.refreshRate + (it.physicalHeight * it.physicalWidth) }?.let { window.attributes.preferredDisplayModeId = it.modeId }
+        display?.supportedModes?.maxByOrNull { it.refreshRate * it.physicalHeight * it.physicalWidth }?.let { window.attributes.preferredDisplayModeId = it.modeId }
 
         binding.gameView.setOnTouchListener(this)