1 files changed, 871 insertions, 0 deletions
diff --git a/src/Ryujinx.HLE/HOS/Services/SurfaceFlinger/BufferQueueProducer.cs b/src/Ryujinx.HLE/HOS/Services/SurfaceFlinger/BufferQueueProducer.cs
new file mode 100644
index 00000000..833bc26e
--- /dev/null
+++ b/src/Ryujinx.HLE/HOS/Services/SurfaceFlinger/BufferQueueProducer.cs
@@ -0,0 +1,871 @@
+using Ryujinx.Common.Logging;
+using Ryujinx.Cpu;
+using Ryujinx.HLE.HOS.Kernel.Threading;
+using Ryujinx.HLE.HOS.Services.Settings;
+using Ryujinx.HLE.HOS.Services.SurfaceFlinger.Types;
+using Ryujinx.HLE.HOS.Services.Time.Clock;
+using System;
+using System.Threading;
+
+namespace Ryujinx.HLE.HOS.Services.SurfaceFlinger
+{
+    class BufferQueueProducer : IGraphicBufferProducer
+    {
+        public BufferQueueCore Core { get; }
+
+        private readonly ITickSource _tickSource;
+
+        private uint _stickyTransform;
+
+        private uint _nextCallbackTicket;
+        private uint _currentCallbackTicket;
+        private uint _callbackTicket;
+
+        private readonly object _callbackLock = new object();
+
+        public BufferQueueProducer(BufferQueueCore core, ITickSource tickSource)
+        {
+            Core = core;
+            _tickSource = tickSource;
+
+            _stickyTransform       = 0;
+            _callbackTicket        = 0;
+            _nextCallbackTicket    = 0;
+            _currentCallbackTicket = 0;
+        }
+
+        public override Status RequestBuffer(int slot, out AndroidStrongPointer<GraphicBuffer> graphicBuffer)
+        {
+            graphicBuffer = new AndroidStrongPointer<GraphicBuffer>();
+
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned)
+                {
+                    return Status.NoInit;
+                }
+
+                if (slot < 0 || slot >= Core.Slots.Length || !Core.IsOwnedByProducerLocked(slot))
+                {
+                    return Status.BadValue;
+                }
+
+                graphicBuffer.Set(Core.Slots[slot].GraphicBuffer);
+
+                Core.Slots[slot].RequestBufferCalled = true;
+
+                return Status.Success;
+            }
+        }
+
+        public override Status SetBufferCount(int bufferCount)
+        {
+            IConsumerListener listener = null;
+
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned)
+                {
+                    return Status.NoInit;
+                }
+
+                if (bufferCount > BufferSlotArray.NumBufferSlots)
+                {
+                    return Status.BadValue;
+                }
+
+                for (int slot = 0; slot < Core.Slots.Length; slot++)
+                {
+                    if (Core.Slots[slot].BufferState == BufferState.Dequeued)
+                    {
+                        return Status.BadValue;
+                    }
+                }
+
+                if (bufferCount == 0)
+                {
+                    Core.OverrideMaxBufferCount = 0;
+                    Core.SignalDequeueEvent();
+
+                    return Status.Success;
+                }
+
+                int minBufferSlots = Core.GetMinMaxBufferCountLocked(false);
+
+                if (bufferCount < minBufferSlots)
+                {
+                    return Status.BadValue;
+                }
+
+                int preallocatedBufferCount = GetPreallocatedBufferCountLocked();
+
+                if (preallocatedBufferCount <= 0)
+                {
+                    Core.Queue.Clear();
+                    Core.FreeAllBuffersLocked();
+                }
+                else if (preallocatedBufferCount < bufferCount)
+                {
+                    Logger.Error?.Print(LogClass.SurfaceFlinger, "Not enough buffers. Try with more pre-allocated buffers");
+
+                    return Status.Success;
+                }
+
+                Core.OverrideMaxBufferCount = bufferCount;
+
+                Core.SignalDequeueEvent();
+                Core.SignalWaitBufferFreeEvent();
+
+                listener = Core.ConsumerListener;
+            }
+
+            listener?.OnBuffersReleased();
+
+            return Status.Success;
+        }
+
+        public override Status DequeueBuffer(out int slot,
+                                             out AndroidFence fence,
+                                             bool async,
+                                             uint width,
+                                             uint height,
+                                             PixelFormat format,
+                                             uint usage)
+        {
+            if ((width == 0 && height != 0) || (height == 0 && width != 0))
+            {
+                slot  = BufferSlotArray.InvalidBufferSlot;
+                fence = AndroidFence.NoFence;
+
+                return Status.BadValue;
+            }
+
+            Status returnFlags = Status.Success;
+
+            bool attachedByConsumer = false;
+
+            lock (Core.Lock)
+            {
+                if (format == PixelFormat.Unknown)
+                {
+                    format = Core.DefaultBufferFormat;
+                }
+
+                usage |= Core.ConsumerUsageBits;
+
+                Status status = WaitForFreeSlotThenRelock(async, out slot, out returnFlags);
+
+                if (status != Status.Success)
+                {
+                    slot  = BufferSlotArray.InvalidBufferSlot;
+                    fence = AndroidFence.NoFence;
+
+                    return status;
+                }
+
+                if (slot == BufferSlotArray.InvalidBufferSlot)
+                {
+                    fence = AndroidFence.NoFence;
+
+                    Logger.Error?.Print(LogClass.SurfaceFlinger, "No available buffer slots");
+
+                    return Status.Busy;
+                }
+
+                attachedByConsumer = Core.Slots[slot].AttachedByConsumer;
+
+                if (width == 0 || height == 0)
+                {
+                    width  = (uint)Core.DefaultWidth;
+                    height = (uint)Core.DefaultHeight;
+                }
+
+                GraphicBuffer graphicBuffer = Core.Slots[slot].GraphicBuffer.Object;
+
+                if (Core.Slots[slot].GraphicBuffer.IsNull
+                    || graphicBuffer.Width != width
+                    || graphicBuffer.Height != height
+                    || graphicBuffer.Format != format
+                    || (graphicBuffer.Usage & usage) != usage)
+                {
+                    if (!Core.Slots[slot].IsPreallocated)
+                    {
+                        slot  = BufferSlotArray.InvalidBufferSlot;
+                        fence = AndroidFence.NoFence;
+
+                        return Status.NoMemory;
+                    }
+                    else
+                    {
+                        Logger.Error?.Print(LogClass.SurfaceFlinger,
+                                            $"Preallocated buffer mismatch - slot {slot}\n" +
+                                            $"available: Width = {graphicBuffer.Width} Height = {graphicBuffer.Height} Format = {graphicBuffer.Format} Usage = {graphicBuffer.Usage:x} " +
+                                            $"requested: Width = {width} Height = {height} Format = {format} Usage = {usage:x}");
+
+                        slot  = BufferSlotArray.InvalidBufferSlot;
+                        fence = AndroidFence.NoFence;
+
+                        return Status.NoInit;
+                    }
+                }
+
+                Core.Slots[slot].BufferState = BufferState.Dequeued;
+
+                Core.UpdateMaxBufferCountCachedLocked(slot);
+
+                fence = Core.Slots[slot].Fence;
+
+                Core.Slots[slot].Fence            = AndroidFence.NoFence;
+                Core.Slots[slot].QueueTime        = TimeSpanType.Zero;
+                Core.Slots[slot].PresentationTime = TimeSpanType.Zero;
+
+                Core.CheckSystemEventsLocked(Core.GetMaxBufferCountLocked(async));
+            }
+
+            if (attachedByConsumer)
+            {
+                returnFlags |= Status.BufferNeedsReallocation;
+            }
+
+            return returnFlags;
+        }
+
+        public override Status DetachBuffer(int slot)
+        {
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned)
+                {
+                    return Status.NoInit;
+                }
+
+                if (slot < 0 || slot >= Core.Slots.Length || !Core.IsOwnedByProducerLocked(slot))
+                {
+                    return Status.BadValue;
+                }
+
+                if (!Core.Slots[slot].RequestBufferCalled)
+                {
+                    Logger.Error?.Print(LogClass.SurfaceFlinger, $"Slot {slot} was detached without requesting a buffer");
+
+                    return Status.BadValue;
+                }
+
+                Core.FreeBufferLocked(slot);
+                Core.SignalDequeueEvent();
+
+                return Status.Success;
+            }
+        }
+
+        public override Status DetachNextBuffer(out AndroidStrongPointer<GraphicBuffer> graphicBuffer, out AndroidFence fence)
+        {
+            lock (Core.Lock)
+            {
+                Core.WaitWhileAllocatingLocked();
+
+                if (Core.IsAbandoned)
+                {
+                    graphicBuffer = default;
+                    fence         = AndroidFence.NoFence;
+
+                    return Status.NoInit;
+                }
+
+                int nextBufferSlot = BufferSlotArray.InvalidBufferSlot;
+
+                for (int slot = 0; slot < Core.Slots.Length; slot++)
+                {
+                    if (Core.Slots[slot].BufferState == BufferState.Free && !Core.Slots[slot].GraphicBuffer.IsNull)
+                    {
+                        if (nextBufferSlot == BufferSlotArray.InvalidBufferSlot || Core.Slots[slot].FrameNumber < Core.Slots[nextBufferSlot].FrameNumber)
+                        {
+                            nextBufferSlot = slot;
+                        }
+                    }
+                }
+
+                if (nextBufferSlot == BufferSlotArray.InvalidBufferSlot)
+                {
+                    graphicBuffer = default;
+                    fence         = AndroidFence.NoFence;
+
+                    return Status.NoMemory;
+                }
+
+                graphicBuffer = Core.Slots[nextBufferSlot].GraphicBuffer;
+                fence         = Core.Slots[nextBufferSlot].Fence;
+
+                Core.FreeBufferLocked(nextBufferSlot);
+
+                return Status.Success;
+            }
+        }
+
+        public override Status AttachBuffer(out int slot, AndroidStrongPointer<GraphicBuffer> graphicBuffer)
+        {
+            lock (Core.Lock)
+            {
+                Core.WaitWhileAllocatingLocked();
+
+                Status status = WaitForFreeSlotThenRelock(false, out slot, out Status returnFlags);
+
+                if (status != Status.Success)
+                {
+                    return status;
+                }
+
+                if (slot == BufferSlotArray.InvalidBufferSlot)
+                {
+                    Logger.Error?.Print(LogClass.SurfaceFlinger, "No available buffer slots");
+
+                    return Status.Busy;
+                }
+
+                Core.UpdateMaxBufferCountCachedLocked(slot);
+
+                Core.Slots[slot].GraphicBuffer.Set(graphicBuffer);
+
+                Core.Slots[slot].BufferState         = BufferState.Dequeued;
+                Core.Slots[slot].Fence               = AndroidFence.NoFence;
+                Core.Slots[slot].RequestBufferCalled = true;
+
+                return returnFlags;
+            }
+        }
+
+        public override Status QueueBuffer(int slot, ref QueueBufferInput input, out QueueBufferOutput output)
+        {
+            output = default;
+
+            switch (input.ScalingMode)
+            {
+                case NativeWindowScalingMode.Freeze:
+                case NativeWindowScalingMode.ScaleToWindow:
+                case NativeWindowScalingMode.ScaleCrop:
+                case NativeWindowScalingMode.Unknown:
+                case NativeWindowScalingMode.NoScaleCrop:
+                    break;
+                default:
+                    return Status.BadValue;
+            }
+
+            BufferItem item = new BufferItem();
+
+            IConsumerListener frameAvailableListener = null;
+            IConsumerListener frameReplaceListener   = null;
+
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned)
+                {
+                    return Status.NoInit;
+                }
+
+                int maxBufferCount = Core.GetMaxBufferCountLocked(input.Async != 0);
+
+                if (input.Async != 0 && Core.OverrideMaxBufferCount != 0 && Core.OverrideMaxBufferCount < maxBufferCount)
+                {
+                    return Status.BadValue;
+                }
+
+                if (slot < 0 || slot >= Core.Slots.Length || !Core.IsOwnedByProducerLocked(slot))
+                {
+                    return Status.BadValue;
+                }
+
+                if (!Core.Slots[slot].RequestBufferCalled)
+                {
+                    Logger.Error?.Print(LogClass.SurfaceFlinger, $"Slot {slot} was queued without requesting a buffer");
+
+                    return Status.BadValue;
+                }
+
+                input.Crop.Intersect(Core.Slots[slot].GraphicBuffer.Object.ToRect(), out Rect croppedRect);
+
+                if (croppedRect != input.Crop)
+                {
+                    return Status.BadValue;
+                }
+
+                Core.Slots[slot].Fence       = input.Fence;
+                Core.Slots[slot].BufferState = BufferState.Queued;
+                Core.FrameCounter++;
+                Core.Slots[slot].FrameNumber      = Core.FrameCounter;
+                Core.Slots[slot].QueueTime        = TimeSpanType.FromTimeSpan(_tickSource.ElapsedTime);
+                Core.Slots[slot].PresentationTime = TimeSpanType.Zero;
+
+                item.AcquireCalled             = Core.Slots[slot].AcquireCalled;
+                item.Crop                      = input.Crop;
+                item.Transform                 = input.Transform;
+                item.TransformToDisplayInverse = (input.Transform & NativeWindowTransform.InverseDisplay) == NativeWindowTransform.InverseDisplay;
+                item.ScalingMode               = input.ScalingMode;
+                item.Timestamp                 = input.Timestamp;
+                item.IsAutoTimestamp           = input.IsAutoTimestamp != 0;
+                item.SwapInterval              = input.SwapInterval;
+                item.FrameNumber               = Core.FrameCounter;
+                item.Slot                      = slot;
+                item.Fence                     = input.Fence;
+                item.IsDroppable               = Core.DequeueBufferCannotBlock || input.Async != 0;
+
+                item.GraphicBuffer.Set(Core.Slots[slot].GraphicBuffer);
+                item.GraphicBuffer.Object.IncrementNvMapHandleRefCount(Core.Owner);
+
+                Core.BufferHistoryPosition = (Core.BufferHistoryPosition + 1) % BufferQueueCore.BufferHistoryArraySize;
+
+                Core.BufferHistory[Core.BufferHistoryPosition] = new BufferInfo
+                {
+                    FrameNumber = Core.FrameCounter,
+                    QueueTime   = Core.Slots[slot].QueueTime,
+                    State       = BufferState.Queued
+                };
+
+                _stickyTransform = input.StickyTransform;
+
+                if (Core.Queue.Count == 0)
+                {
+                    Core.Queue.Add(item);
+
+                    frameAvailableListener = Core.ConsumerListener;
+                }
+                else
+                {
+                    BufferItem frontItem = Core.Queue[0];
+
+                    if (frontItem.IsDroppable)
+                    {
+                        if (Core.StillTracking(ref frontItem))
+                        {
+                            Core.Slots[slot].BufferState = BufferState.Free;
+                            Core.Slots[slot].FrameNumber = 0;
+                        }
+
+                        Core.Queue.RemoveAt(0);
+                        Core.Queue.Insert(0, item);
+
+                        frameReplaceListener = Core.ConsumerListener;
+                    }
+                    else
+                    {
+                        Core.Queue.Add(item);
+
+                        frameAvailableListener = Core.ConsumerListener;
+                    }
+                }
+
+                Core.BufferHasBeenQueued = true;
+                Core.SignalDequeueEvent();
+
+                Core.CheckSystemEventsLocked(maxBufferCount);
+
+                output = new QueueBufferOutput
+                {
+                    Width             = (uint)Core.DefaultWidth,
+                    Height            = (uint)Core.DefaultHeight,
+                    TransformHint     = Core.TransformHint,
+                    NumPendingBuffers = (uint)Core.Queue.Count
+                };
+
+                if ((input.StickyTransform & 8) != 0)
+                {
+                    output.TransformHint |= NativeWindowTransform.ReturnFrameNumber;
+                    output.FrameNumber = Core.Slots[slot].FrameNumber;
+                }
+
+                _callbackTicket = _nextCallbackTicket++;
+            }
+
+            lock (_callbackLock)
+            {
+                while (_callbackTicket != _currentCallbackTicket)
+                {
+                    Monitor.Wait(_callbackLock);
+                }
+
+                frameAvailableListener?.OnFrameAvailable(ref item);
+                frameReplaceListener?.OnFrameReplaced(ref item);
+
+                _currentCallbackTicket++;
+
+                Monitor.PulseAll(_callbackLock);
+            }
+
+            Core.SignalQueueEvent();
+
+            return Status.Success;
+        }
+
+        public override void CancelBuffer(int slot, ref AndroidFence fence)
+        {
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned || slot < 0 || slot >= Core.Slots.Length || !Core.IsOwnedByProducerLocked(slot))
+                {
+                    return;
+                }
+
+                Core.Slots[slot].BufferState = BufferState.Free;
+                Core.Slots[slot].FrameNumber = 0;
+                Core.Slots[slot].Fence       = fence;
+                Core.SignalDequeueEvent();
+                Core.SignalWaitBufferFreeEvent();
+            }
+        }
+
+        public override Status Query(NativeWindowAttribute what, out int outValue)
+        {
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned)
+                {
+                    outValue = 0;
+                    return Status.NoInit;
+                }
+
+                switch (what)
+                {
+                    case NativeWindowAttribute.Width:
+                        outValue = Core.DefaultWidth;
+                        return Status.Success;
+                    case NativeWindowAttribute.Height:
+                        outValue = Core.DefaultHeight;
+                        return Status.Success;
+                    case NativeWindowAttribute.Format:
+                        outValue = (int)Core.DefaultBufferFormat;
+                        return Status.Success;
+                    case NativeWindowAttribute.MinUnqueuedBuffers:
+                        outValue = Core.GetMinUndequeuedBufferCountLocked(false);
+                        return Status.Success;
+                    case NativeWindowAttribute.ConsumerRunningBehind:
+                        outValue = Core.Queue.Count > 1 ? 1 : 0;
+                        return Status.Success;
+                    case NativeWindowAttribute.ConsumerUsageBits:
+                        outValue = (int)Core.ConsumerUsageBits;
+                        return Status.Success;
+                    case NativeWindowAttribute.MaxBufferCountAsync:
+                        outValue = Core.GetMaxBufferCountLocked(true);
+                        return Status.Success;
+                    default:
+                        outValue = 0;
+                        return Status.BadValue;
+                }
+            }
+        }
+
+        public override Status Connect(IProducerListener listener, NativeWindowApi api, bool producerControlledByApp, out QueueBufferOutput output)
+        {
+            output = new QueueBufferOutput();
+
+            lock (Core.Lock)
+            {
+                if (Core.IsAbandoned || Core.ConsumerListener == null)
+                {
+                    return Status.NoInit;
+                }
+
+                if (Core.ConnectedApi != NativeWindowApi.NoApi)
+                {
+                    return Status.BadValue;
+                }
+
+                Core.BufferHasBeenQueued      = false;
+                Core.DequeueBufferCannotBlock = Core.ConsumerControlledByApp && producerControlledByApp;
+
+                switch (api)
+                {
+                    case NativeWindowApi.NVN:
+                    case NativeWindowApi.CPU:
+                    case NativeWindowApi.Media:
+                    case NativeWindowApi.Camera:
+                        Core.ProducerListener = listener;
+                        Core.ConnectedApi     = api;
+
+                        output.Width             = (uint)Core.DefaultWidth;
+                        output.Height            = (uint)Core.DefaultHeight;
+                        output.TransformHint     = Core.TransformHint;
+                        output.NumPendingBuffers = (uint)Core.Queue.Count;
+
+                        if (NxSettings.Settings.TryGetValue("nv!nvn_no_vsync_capability", out object noVSyncCapability) && (bool)noVSyncCapability)
+                        {
+                            output.TransformHint |= NativeWindowTransform.NoVSyncCapability;
+                        }
+
+                        return Status.Success;
+                    default:
+                        return Status.BadValue;
+                }
+            }
+        }
+
+        public override Status Disconnect(NativeWindowApi api)
+        {
+            IProducerListener producerListener = null;
+
+            Status status = Status.BadValue;
+
+            lock (Core.Lock)
+            {
+                Core.WaitWhileAllocatingLocked();
+
+                if (Core.IsAbandoned)
+                {
+                    return Status.Success;
+                }
+
+                switch (api)
+                {
+                    case NativeWindowApi.NVN:
+                    case NativeWindowApi.CPU:
+                    case NativeWindowApi.Media:
+                    case NativeWindowApi.Camera:
+                        if (Core.ConnectedApi == api)
+                        {
+                            Core.Queue.Clear();
+                            Core.FreeAllBuffersLocked();
+                            Core.SignalDequeueEvent();
+
+                            producerListener = Core.ProducerListener;
+
+                            Core.ProducerListener = null;
+                            Core.ConnectedApi     = NativeWindowApi.NoApi;
+
+                            Core.SignalWaitBufferFreeEvent();
+                            Core.SignalFrameAvailableEvent();
+
+                            status = Status.Success;
+                        }
+                        break;
+                }
+            }
+
+            producerListener?.OnBufferReleased();
+
+            return status;
+        }
+
+        private int GetPreallocatedBufferCountLocked()
+        {
+            int bufferCount = 0;
+
+            for (int i = 0; i < Core.Slots.Length; i++)
+            {
+                if (Core.Slots[i].IsPreallocated)
+                {
+                    bufferCount++;
+                }
+            }
+
+            return bufferCount;
+        }
+
+        public override Status SetPreallocatedBuffer(int slot, AndroidStrongPointer<GraphicBuffer> graphicBuffer)
+        {
+            if (slot < 0 || slot >= Core.Slots.Length)
+            {
+                return Status.BadValue;
+            }
+
+            lock (Core.Lock)
+            {
+                Core.Slots[slot].BufferState           = BufferState.Free;
+                Core.Slots[slot].Fence                 = AndroidFence.NoFence;
+                Core.Slots[slot].RequestBufferCalled   = false;
+                Core.Slots[slot].AcquireCalled         = false;
+                Core.Slots[slot].NeedsCleanupOnRelease = false;
+                Core.Slots[slot].IsPreallocated        = !graphicBuffer.IsNull;
+                Core.Slots[slot].FrameNumber           = 0;
+
+                Core.Slots[slot].GraphicBuffer.Set(graphicBuffer);
+
+                if (!Core.Slots[slot].GraphicBuffer.IsNull)
+                {
+                    Core.Slots[slot].GraphicBuffer.Object.Buffer.Usage &= (int)Core.ConsumerUsageBits;
+                }
+
+                Core.OverrideMaxBufferCount = GetPreallocatedBufferCountLocked();
+                Core.UseAsyncBuffer = false;
+
+                if (!graphicBuffer.IsNull)
+                {
+                    // NOTE: Nintendo set the default width, height and format from the GraphicBuffer..
+                    //       This is entirely wrong and should only be controlled by the consumer...
+                    Core.DefaultWidth        = graphicBuffer.Object.Width;
+                    Core.DefaultHeight       = graphicBuffer.Object.Height;
+                    Core.DefaultBufferFormat = graphicBuffer.Object.Format;
+                }
+                else
+                {
+                    bool allBufferFreed = true;
+
+                    for (int i = 0; i < Core.Slots.Length; i++)
+                    {
+                        if (!Core.Slots[i].GraphicBuffer.IsNull)
+                        {
+                            allBufferFreed = false;
+                            break;
+                        }
+                    }
+
+                    if (allBufferFreed)
+                    {
+                        Core.Queue.Clear();
+                        Core.FreeAllBuffersLocked();
+                        Core.SignalDequeueEvent();
+                        Core.SignalWaitBufferFreeEvent();
+                        Core.SignalFrameAvailableEvent();
+
+                        return Status.Success;
+                    }
+                }
+
+                Core.SignalDequeueEvent();
+                Core.SignalWaitBufferFreeEvent();
+
+                return Status.Success;
+            }
+        }
+
+        private Status WaitForFreeSlotThenRelock(bool async, out int freeSlot, out Status returnStatus)
+        {
+            bool tryAgain = true;
+
+            freeSlot     = BufferSlotArray.InvalidBufferSlot;
+            returnStatus = Status.Success;
+
+            while (tryAgain)
+            {
+                if (Core.IsAbandoned)
+                {
+                    freeSlot = BufferSlotArray.InvalidBufferSlot;
+
+                    return Status.NoInit;
+                }
+
+                int maxBufferCount = Core.GetMaxBufferCountLocked(async);
+
+                if (async && Core.OverrideMaxBufferCount != 0 && Core.OverrideMaxBufferCount < maxBufferCount)
+                {
+                    freeSlot = BufferSlotArray.InvalidBufferSlot;
+
+                    return Status.BadValue;
+                }
+
+
+                if (maxBufferCount < Core.MaxBufferCountCached)
+                {
+                    for (int slot = maxBufferCount; slot < Core.MaxBufferCountCached; slot++)
+                    {
+                        if (Core.Slots[slot].BufferState == BufferState.Free && !Core.Slots[slot].GraphicBuffer.IsNull && !Core.Slots[slot].IsPreallocated)
+                        {
+                            Core.FreeBufferLocked(slot);
+                            returnStatus |= Status.ReleaseAllBuffers;
+                        }
+                    }
+                }
+
+                freeSlot = BufferSlotArray.InvalidBufferSlot;
+
+                int dequeuedCount = 0;
+                int acquiredCount = 0;
+
+                for (int slot = 0; slot < maxBufferCount; slot++)
+                {
+                    switch (Core.Slots[slot].BufferState)
+                    {
+                        case BufferState.Acquired:
+                            acquiredCount++;
+                            break;
+                        case BufferState.Dequeued:
+                            dequeuedCount++;
+                            break;
+                        case BufferState.Free:
+                            if (freeSlot == BufferSlotArray.InvalidBufferSlot || Core.Slots[slot].FrameNumber < Core.Slots[freeSlot].FrameNumber)
+                            {
+                                freeSlot = slot;
+                            }
+                            break;
+                        default:
+                            break;
+                    }
+                }
+
+                // The producer SHOULD call SetBufferCount otherwise it's not allowed to dequeue multiple buffers.
+                if (Core.OverrideMaxBufferCount == 0 && dequeuedCount > 0)
+                {
+                    return Status.InvalidOperation;
+                }
+
+                if (Core.BufferHasBeenQueued)
+                {
+                    int newUndequeuedCount = maxBufferCount - (dequeuedCount + 1);
+                    int minUndequeuedCount = Core.GetMinUndequeuedBufferCountLocked(async);
+
+                    if (newUndequeuedCount < minUndequeuedCount)
+                    {
+                        Logger.Error?.Print(LogClass.SurfaceFlinger, $"Min undequeued buffer count ({minUndequeuedCount}) exceeded (dequeued = {dequeuedCount} undequeued = {newUndequeuedCount})");
+
+                        return Status.InvalidOperation;
+                    }
+                }
+
+                bool tooManyBuffers = Core.Queue.Count > maxBufferCount;
+
+                tryAgain = freeSlot == BufferSlotArray.InvalidBufferSlot || tooManyBuffers;
+
+                if (tryAgain)
+                {
+                    if (async || (Core.DequeueBufferCannotBlock && acquiredCount < Core.MaxAcquiredBufferCount))
+                    {
+                        Core.CheckSystemEventsLocked(maxBufferCount);
+
+                        return Status.WouldBlock;
+                    }
+
+                    Core.WaitDequeueEvent();
+
+                    if (!Core.Active)
+                    {
+                        break;
+                    }
+                }
+            }
+
+            return Status.Success;
+        }
+
+        protected override KReadableEvent GetWaitBufferFreeEvent()
+        {
+            return Core.GetWaitBufferFreeEvent();
+        }
+
+        public override Status GetBufferHistory(int bufferHistoryCount, out Span<BufferInfo> bufferInfos)
+        {
+            if (bufferHistoryCount <= 0)
+            {
+                bufferInfos = Span<BufferInfo>.Empty;
+
+                return Status.BadValue;
+            }
+
+            lock (Core.Lock)
+            {
+                bufferHistoryCount = Math.Min(bufferHistoryCount, Core.BufferHistory.Length);
+
+                BufferInfo[] result = new BufferInfo[bufferHistoryCount];
+
+                uint position = Core.BufferHistoryPosition;
+
+                for (uint i = 0; i < bufferHistoryCount; i++)
+                {
+                    result[i] = Core.BufferHistory[(position - i) % Core.BufferHistory.Length];
+
+                    position--;
+                }
+
+                bufferInfos = result;
+
+                return Status.Success;
+            }
+        }
+    }
+}