Revert "[dxvk] Fix lack of forward progress guarantee in presenter"

This reverts commit efeb15edbd.

src/dxvk/dxvk_presenter.cpp

@@ -259,16 +259,9 @@ namespace dxvk {
       return;
 
     if (m_device->features().khrPresentWait.presentWait) {
-      bool canSignal = false;
-
-      { std::unique_lock lock(m_frameMutex);
-
-        m_lastSignaled = frameId;
-        canSignal = m_lastCompleted >= frameId;
-      }
-
-      if (canSignal)
-        m_signal->signal(frameId);
+      std::lock_guard lock(m_frameMutex);
+      m_lastSignaled = frameId;
+      m_frameCond.notify_one();
     } else {
       m_fpsLimiter.delay(tracker);
       m_signal->signal(frameId);
@@ -1210,26 +1203,25 @@ namespace dxvk {
   void Presenter::runFrameThread() {
     env::setThreadName("dxvk-frame");
 
-    while (true) {
-      PresenterFrame frame = { };
+    std::unique_lock lock(m_frameMutex);
 
+    while (true) {
       // Wait for all GPU work for this frame to complete in order to maintain
       // ordering guarantees of the frame signal w.r.t. objects being released
-      { std::unique_lock lock(m_frameMutex);
+      m_frameCond.wait(lock, [this] {
+        return !m_frameQueue.empty() && m_frameQueue.front().frameId <= m_lastSignaled;
+      });
 
-        m_frameCond.wait(lock, [this] {
-          return !m_frameQueue.empty();
-        });
+      // Use a frame ID of 0 as an exit condition
+      PresenterFrame frame = m_frameQueue.front();
 
-        // Use a frame ID of 0 as an exit condition
-        frame = m_frameQueue.front();
-
-        if (!frame.frameId) {
-          m_frameQueue.pop();
-          return;
-        }
+      if (!frame.frameId) {
+        m_frameQueue.pop();
+        return;
       }
 
+      lock.unlock();
+
       // If the present operation has succeeded, actually wait for it to complete.
       // Don't bother with it on MAILBOX / IMMEDIATE modes since doing so would
       // restrict us to the display refresh rate on some platforms (XWayland).
@@ -1246,28 +1238,21 @@ namespace dxvk {
       if (frame.tracker)
         frame.tracker->notifyGpuPresentEnd(frame.frameId);
 
-      // Apply FPS limiter here to align it as closely with scanout as we can,
+      // Apply FPS limtier here to align it as closely with scanout as we can,
       // and delay signaling the frame latency event to emulate behaviour of a
       // low refresh rate display as closely as we can.
       m_fpsLimiter.delay(frame.tracker);
       frame.tracker = nullptr;
 
-      // Wake up any thread that may be waiting for the queue to become empty
-      bool canSignal = false;
-
-      { std::unique_lock lock(m_frameMutex);
-
-        m_frameQueue.pop();
-        m_frameDrain.notify_one();
-
-        m_lastCompleted = frame.frameId;
-        canSignal = m_lastSignaled >= frame.frameId;
-      }
-
       // Always signal even on error, since failures here
       // are transparent to the front-end.
-      if (canSignal)
-        m_signal->signal(frame.frameId);
+      m_signal->signal(frame.frameId);
+
+      // Wake up any thread that may be waiting for the queue to become empty
+      lock.lock();
+
+      m_frameQueue.pop();
+      m_frameDrain.notify_one();
     }
   }
 

src/dxvk/dxvk_presenter.h

@@ -315,7 +315,6 @@ namespace dxvk {
     std::queue<PresenterFrame>  m_frameQueue;
 
     uint64_t                    m_lastSignaled = 0u;
-    uint64_t                    m_lastCompleted = 0u;
 
     alignas(CACHE_LINE_SIZE)
     FpsLimiter                  m_fpsLimiter;