From 6433b1dfd67f4c4f0c4b2e3742dc437a0d1e906e Mon Sep 17 00:00:00 2001
From: bunnei <bunneidev@gmail.com>
Date: Wed, 16 Dec 2020 21:09:06 -0800
Subject: service: nvflinger: Improve synchronization for BufferQueue.

- Use proper mechanisms for blocking on DequeueBuffer.
- Ensure service thread terminates on emulation Shutdown.
---
 src/core/hle/service/nvflinger/buffer_queue.cpp | 40 ++++++++++++++++++++++---
 1 file changed, 36 insertions(+), 4 deletions(-)

(limited to 'src/core/hle/service/nvflinger/buffer_queue.cpp')

diff --git a/src/core/hle/service/nvflinger/buffer_queue.cpp b/src/core/hle/service/nvflinger/buffer_queue.cpp
index 377f47e8e..c8c6a4d64 100644
--- a/src/core/hle/service/nvflinger/buffer_queue.cpp
+++ b/src/core/hle/service/nvflinger/buffer_queue.cpp
@@ -25,7 +25,12 @@ void BufferQueue::SetPreallocatedBuffer(u32 slot, const IGBPBuffer& igbp_buffer)
     ASSERT(slot < buffer_slots);
     LOG_WARNING(Service, "Adding graphics buffer {}", slot);
 
-    free_buffers.push_back(slot);
+    {
+        std::unique_lock lock{queue_mutex};
+        free_buffers.push_back(slot);
+    }
+    condition.notify_one();
+
     buffers[slot] = {
         .slot = slot,
         .status = Buffer::Status::Free,
@@ -41,10 +46,20 @@ void BufferQueue::SetPreallocatedBuffer(u32 slot, const IGBPBuffer& igbp_buffer)
 
 std::optional<std::pair<u32, Service::Nvidia::MultiFence*>> BufferQueue::DequeueBuffer(u32 width,
                                                                                        u32 height) {
+    // Wait for first request before trying to dequeue
+    {
+        std::unique_lock lock{queue_mutex};
+        condition.wait(lock, [this] { return !free_buffers.empty() || !is_connect; });
+    }
 
-    if (free_buffers.empty()) {
+    if (!is_connect) {
+        // Buffer was disconnected while the thread was blocked, this is most likely due to
+        // emulation being stopped
         return std::nullopt;
     }
+
+    std::unique_lock lock{queue_mutex};
+
     auto f_itr = free_buffers.begin();
     auto slot = buffers.size();
 
@@ -97,7 +112,11 @@ void BufferQueue::CancelBuffer(u32 slot, const Service::Nvidia::MultiFence& mult
     buffers[slot].multi_fence = multi_fence;
     buffers[slot].swap_interval = 0;
 
-    free_buffers.push_back(slot);
+    {
+        std::unique_lock lock{queue_mutex};
+        free_buffers.push_back(slot);
+    }
+    condition.notify_one();
 
     buffer_wait_event.writable->Signal();
 }
@@ -127,15 +146,28 @@ void BufferQueue::ReleaseBuffer(u32 slot) {
     ASSERT(buffers[slot].slot == slot);
 
     buffers[slot].status = Buffer::Status::Free;
-    free_buffers.push_back(slot);
+    {
+        std::unique_lock lock{queue_mutex};
+        free_buffers.push_back(slot);
+    }
+    condition.notify_one();
 
     buffer_wait_event.writable->Signal();
 }
 
+void BufferQueue::Connect() {
+    queue_sequence.clear();
+    id = 1;
+    layer_id = 1;
+    is_connect = true;
+}
+
 void BufferQueue::Disconnect() {
     buffers.fill({});
     queue_sequence.clear();
     buffer_wait_event.writable->Signal();
+    is_connect = false;
+    condition.notify_one();
 }
 
 u32 BufferQueue::Query(QueryType type) {
-- 
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