Implementing SetBufferCount in BufferQueue

src/core/hle/service/nvflinger/buffer_queue.cpp

@@ -15,7 +15,7 @@
 namespace Service::NVFlinger {
 
 BufferQueue::BufferQueue(Kernel::KernelCore& kernel, u32 id, u64 layer_id)
-    : id(id), layer_id(layer_id) {
+    : id(id), layer_id(layer_id), max_buffer_count(0) {
     buffer_wait_event = Kernel::WritableEvent::CreateEventPair(kernel, "BufferQueue NativeHandle");
 }
 
@@ -33,6 +33,10 @@ void BufferQueue::SetPreallocatedBuffer(u32 slot, const IGBPBuffer& igbp_buffer)
     buffer_wait_event.writable->Signal();
 }
 
+void BufferQueue::SetBufferCount(u32 bufferCount) {
+    max_buffer_count = bufferCount;
+}
+
 std::optional<std::pair<u32, Service::Nvidia::MultiFence*>> BufferQueue::DequeueBuffer(u32 width,
                                                                                        u32 height) {
     auto itr = std::find_if(queue.begin(), queue.end(), [&](const Buffer& buffer) {
@@ -47,6 +51,9 @@ std::optional<std::pair<u32, Service::Nvidia::MultiFence*>> BufferQueue::Dequeue
     });
 
     if (itr == queue.end()) {
+        if (queue.size() < max_buffer_count) {
+            // TODO: Actually implement that create a new IGBPBuffer from GPU
+        }
         return {};
     }
 

src/core/hle/service/nvflinger/buffer_queue.h

@@ -79,6 +79,7 @@ public:
     };
 
     void SetPreallocatedBuffer(u32 slot, const IGBPBuffer& igbp_buffer);
+    void SetBufferCount(u32 bufferCount);
     std::optional<std::pair<u32, Service::Nvidia::MultiFence*>> DequeueBuffer(u32 width,
                                                                               u32 height);
     const IGBPBuffer& RequestBuffer(u32 slot) const;
@@ -104,6 +105,7 @@ private:
     std::vector<Buffer> queue;
     std::list<u32> queue_sequence;
     Kernel::EventPair buffer_wait_event;
+    u32 max_buffer_count;
 };
 
 } // namespace Service::NVFlinger

src/core/hle/service/vi/vi.cpp

@@ -379,6 +379,28 @@ protected:
     NVFlinger::IGBPBuffer buffer;
 };
 
+class IGBPSetBufferCountRequestParcel : public Parcel {
+public:
+    explicit IGBPSetBufferCountRequestParcel(std::vector<u8> buffer) : Parcel(std::move(buffer)) {
+        Deserialize();
+    }
+    ~IGBPSetBufferCountRequestParcel() override = default;
+
+    void DeserializeData() override {
+        std::u16string token = ReadInterfaceToken();
+        count = Read<u32_le>();
+    }
+
+    u32_le count;
+};
+
+class IGBPSetBufferCountResponseParcel : public Parcel {
+protected:
+    void SerializeData() override {
+        Write<u32>(0);
+    }
+};
+
 class IGBPQueueBufferRequestParcel : public Parcel {
 public:
     explicit IGBPQueueBufferRequestParcel(std::vector<u8> buffer) : Parcel(std::move(buffer)) {
@@ -588,6 +610,13 @@ private:
 
             IGBPEmptyResponseParcel response{};
             ctx.WriteBuffer(response.Serialize());
+        } else if (transaction == TransactionId::SetBufferCount) {
+            IGBPSetBufferCountRequestParcel request{ctx.ReadBuffer()};
+
+            buffer_queue.SetBufferCount(request.count);
+
+            IGBPSetBufferCountResponseParcel response{};
+            ctx.WriteBuffer(response.Serialize());
         } else {
             ASSERT_MSG(false, "Unimplemented");
         }