[core/nvnflinger] Rewrite GetBufferHistory

src/core/hle/service/nvnflinger/buffer_queue_consumer.cpp

@@ -1,3 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-FileCopyrightText: Copyright 2014 The Android Open Source Project
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -97,18 +98,18 @@ Status BufferQueueConsumer::AcquireBuffer(BufferItem* out_buffer,
         slots[slot].needs_cleanup_on_release = false;
         slots[slot].buffer_state = BufferState::Acquired;
 
+        // Mark tracked buffer history records as acquired
+        for (auto& buffer_history_record : core->buffer_history) {
+            if (buffer_history_record.frame_number == core->frame_counter) {
+                buffer_history_record.state = BufferState::Acquired;
+                break;
+            }
+        }
+
         // TODO: for now, avoid resetting the fence, so that when we next return this
         // slot to the producer, it will wait for the fence to pass. We should fix this
         // by properly waiting for the fence in the BufferItemConsumer.
         // slots[slot].fence = Fence::NoFence();
-
-        const auto target_frame_number = slots[slot].frame_number;
-        for (size_t i = 0; i < core->history.size(); i++) {
-            if (core->history[i].frame_number == target_frame_number) {
-                core->history[i].state = BufferState::Acquired;
-                break;
-            }
-        }
     }
 
     // If the buffer has previously been acquired by the consumer, set graphic_buffer to nullptr to

src/core/hle/service/nvnflinger/buffer_queue_core.cpp

@@ -1,3 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-FileCopyrightText: Copyright 2014 The Android Open Source Project
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -10,12 +11,19 @@
 
 namespace Service::android {
 
-BufferQueueCore::BufferQueueCore() {
-    history.resize(8);
-};
-
+BufferQueueCore::BufferQueueCore() = default;
 BufferQueueCore::~BufferQueueCore() = default;
 
+void BufferQueueCore::PushHistory(u64 frame_number, s64 queue_time, s64 presentation_time, BufferState state) {
+    buffer_history_pos = (buffer_history_pos + 1) % BUFFER_HISTORY_SIZE;
+    buffer_history[buffer_history_pos] = BufferHistoryInfo{
+        .frame_number = frame_number,
+        .queue_time = queue_time,
+        .presentation_time = presentation_time,
+        .state = state,
+    };
+}
+
 void BufferQueueCore::SignalDequeueCondition() {
     dequeue_possible.store(true);
     dequeue_condition.notify_all();
@@ -47,7 +55,7 @@ s32 BufferQueueCore::GetMinMaxBufferCountLocked(bool async) const {
 
 s32 BufferQueueCore::GetMaxBufferCountLocked(bool async) const {
     const auto min_buffer_count = GetMinMaxBufferCountLocked(async);
-    auto max_buffer_count = (std::max)(default_max_buffer_count, min_buffer_count);
+    auto max_buffer_count = std::max(default_max_buffer_count, min_buffer_count);
 
     if (override_max_buffer_count != 0) {
         ASSERT(override_max_buffer_count >= min_buffer_count);

src/core/hle/service/nvnflinger/buffer_queue_core.h

@@ -1,3 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-FileCopyrightText: Copyright 2014 The Android Open Source Project
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -15,6 +16,7 @@
 
 #include "core/hle/service/nvnflinger/buffer_item.h"
 #include "core/hle/service/nvnflinger/buffer_queue_defs.h"
+#include "core/hle/service/nvnflinger/buffer_slot.h"
 #include "core/hle/service/nvnflinger/pixel_format.h"
 #include "core/hle/service/nvnflinger/status.h"
 #include "core/hle/service/nvnflinger/window.h"
@@ -23,22 +25,19 @@ namespace Service::android {
 
 #ifdef _MSC_VER
 #pragma pack(push, 1)
+struct BufferHistoryInfo {
+#elif defined(__GNUC__) || defined(__clang__)
+struct __attribute__((packed)) BufferHistoryInfo {
 #endif
-struct BufferInfo {
     u64 frame_number;
     s64 queue_time;
-    s64 presentation_time{};
-    BufferState state{BufferState::Free};
-}
-#if defined(__GNUC__) || defined(__clang__)
-__attribute__((packed))
-#endif
-;
+    s64 presentation_time;
+    BufferState state;
+};
 #ifdef _MSC_VER
 #pragma pack(pop)
 #endif
-static_assert(sizeof(BufferInfo) == 0x1C,
-              "BufferInfo is an invalid size");
+static_assert(sizeof(BufferHistoryInfo) == 0x1C, "BufferHistoryInfo must be 28 bytes");
 
 class IConsumerListener;
 class IProducerListener;
@@ -49,10 +48,13 @@ class BufferQueueCore final {
 
 public:
     static constexpr s32 INVALID_BUFFER_SLOT = BufferItem::INVALID_BUFFER_SLOT;
+    static constexpr u32 BUFFER_HISTORY_SIZE = 8;
 
     BufferQueueCore();
     ~BufferQueueCore();
 
+    void PushHistory(u64 frame_number, s64 queue_time, s64 presentation_time, BufferState state);
+
 private:
     void SignalDequeueCondition();
     bool WaitForDequeueCondition(std::unique_lock<std::mutex>& lk);
@@ -88,11 +90,11 @@ private:
     const s32 max_acquired_buffer_count{}; // This is always zero on HOS
     bool buffer_has_been_queued{};
     u64 frame_counter{};
+    std::array<BufferHistoryInfo, BUFFER_HISTORY_SIZE> buffer_history{};
+    u32 buffer_history_pos{BUFFER_HISTORY_SIZE-1};
     u32 transform_hint{};
     bool is_allocating{};
     mutable std::condition_variable_any is_allocating_condition;
-
-    std::vector<BufferInfo> history{8};
 };
 
 } // namespace Service::android

src/core/hle/service/nvnflinger/buffer_queue_producer.cpp

@@ -1,3 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-FileCopyrightText: Copyright 2014 The Android Open Source Project
 // SPDX-License-Identifier: GPL-3.0-or-later
@@ -530,11 +531,6 @@ Status BufferQueueProducer::QueueBuffer(s32 slot, const QueueBufferInput& input,
         item.is_droppable = core->dequeue_buffer_cannot_block || async;
         item.swap_interval = swap_interval;
 
-        position = (position + 1) % 8;
-        core->history[position] = {.frame_number = core->frame_counter,
-                                   .queue_time = slots[slot].queue_time,
-                                   .state = BufferState::Queued};
-
         sticky_transform = sticky_transform_;
 
         if (core->queue.empty()) {
@@ -551,6 +547,15 @@ Status BufferQueueProducer::QueueBuffer(s32 slot, const QueueBufferInput& input,
                 // mark it as freed
                 if (core->StillTracking(*front)) {
                     slots[front->slot].buffer_state = BufferState::Free;
+
+                           // Mark tracked buffer history records as free
+                    for (auto& buffer_history_record : core->buffer_history) {
+                        if (buffer_history_record.frame_number == front->frame_number) {
+                            buffer_history_record.state = BufferState::Free;
+                            break;
+                        }
+                    }
+
                            // Reset the frame number of the freed buffer so that it is the first in line to
                            // be dequeued again
                     slots[front->slot].frame_number = 0;
@@ -564,6 +569,7 @@ Status BufferQueueProducer::QueueBuffer(s32 slot, const QueueBufferInput& input,
             }
         }
 
+        core->PushHistory(core->frame_counter, slots[slot].queue_time, slots[slot].presentation_time, BufferState::Queued);
         core->buffer_has_been_queued = true;
         core->SignalDequeueCondition();
         output->Inflate(core->default_width, core->default_height, core->transform_hint,
@@ -938,33 +944,46 @@ void BufferQueueProducer::Transact(u32 code, std::span<const u8> parcel_data,
         break;
     }
     case TransactionId::GetBufferHistory: {
-        LOG_WARNING(Service_Nvnflinger, "called, transaction=GetBufferHistory");
-
-        std::scoped_lock lock{core->mutex};
-
-        auto buffer_history_count = (std::min)(parcel_in.Read<s32>(), (s32)core->history.size());
+        LOG_DEBUG(Service_Nvnflinger, "called, transaction=GetBufferHistory");
 
-        if (buffer_history_count <= 0) {
+        const s32 request = parcel_in.Read<s32>();
+        if (request <= 0) {
             parcel_out.Write(Status::BadValue);
             parcel_out.Write<s32>(0);
-            status = Status::None;
             break;
         }
 
-        auto info = new BufferInfo[buffer_history_count];
-        auto pos = position;
-        for (int i = 0; i < buffer_history_count; i++) {
-            info[i] = core->history[(pos - i) % core->history.size()];
-            LOG_WARNING(Service_Nvnflinger, "frame_number={}, state={}",
-                        core->history[(pos - i) % core->history.size()].frame_number,
-                        (u32)core->history[(pos - i) % core->history.size()].state);
-            pos--;
+        constexpr u32 history_max = BufferQueueCore::BUFFER_HISTORY_SIZE;
+        std::array<BufferHistoryInfo, history_max> buffer_history_snapshot{};
+        s32 valid_index{};
+        {
+            std::scoped_lock lk(core->mutex);
+
+            const u32 current_history_pos = core->buffer_history_pos;
+            u32 index_reversed{};
+            for (u32 i = 0; i < history_max; ++i) {
+                // Wrap values backwards e.g. 7, 6, 5, etc. in the range of 0-7
+                index_reversed = (current_history_pos + history_max - i) % history_max;
+                const auto& current_history_buffer = core->buffer_history[index_reversed];
+
+                       // Here we use the frame number as a terminator.
+                       // Because a buffer without frame_number is not considered complete
+                if (current_history_buffer.frame_number == 0) {
+                    break;
+                }
+
+                buffer_history_snapshot[valid_index] = current_history_buffer;
+                ++valid_index;
+            }
         }
 
+        const s32 limit = std::min(request, valid_index);
         parcel_out.Write(Status::NoError);
-        parcel_out.Write(buffer_history_count);
-        parcel_out.WriteFlattenedObject<BufferInfo>(info);
-        status = Status::None;
+        parcel_out.Write<s32>(limit);
+        for (s32 i = 0; i < limit; ++i) {
+            parcel_out.Write(buffer_history_snapshot[i]);
+        }
+
         break;
     }
     default:
@@ -972,9 +991,7 @@ void BufferQueueProducer::Transact(u32 code, std::span<const u8> parcel_data,
         break;
     }
 
-    if (status != Status::None) {
     parcel_out.Write(status);
-    }
 
     const auto serialized = parcel_out.Serialize();
     std::memcpy(parcel_reply.data(), serialized.data(),

src/core/hle/service/nvnflinger/buffer_queue_producer.h

@@ -1,3 +1,4 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
 // SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
 // SPDX-FileCopyrightText: Copyright 2014 The Android Open Source Project
 // SPDX-License-Identifier: GPL-3.0-or-later

src/core/hle/service/nvnflinger/buffer_slot.h

@@ -15,7 +15,7 @@ namespace Service::android {
 
 class GraphicBuffer;
 
-enum class BufferState : s32 {
+enum class BufferState : u32 {
     Free = 0,
     Dequeued = 1,
     Queued = 2,