[dxvk] Allow for fps limit < 50 fps in low-latency mode

dxvk.conf

@@ -39,7 +39,7 @@
 #
 # Supported values: "max-frame-latency", "low-latency", "min-latency"
 
-# dxvk.framePacing = ""
+# dxvk.framePace = ""
 
 
 # Allows fine-tuning the low-latency frame pacing mode.
@@ -149,7 +149,7 @@
 #         The implementation will either use VK_NV_low_latency2 if supported
 #         by the driver, or a custom algorithm.
 # - False: Disable Reflex support as well as built-in latency reduction.
-#         This build defaults to False to enable dxvk.framePacing. You need to
+#         This build defaults to False to enable dxvk.framePace. You need to
 #         enable Reflex manually (Auto) until we support switching back and
 #         forth between Reflex and the low-latency frame pacing - for example
 #         via the ingame options - and more critically we want to enable

src/dxvk/framepacer/dxvk_framepacer_mode_low_latency.h

@@ -164,7 +164,8 @@ namespace dxvk {
       int32_t frametime = std::chrono::duration_cast<microseconds>( t - m_lastStart ).count();
       int32_t frametimeDiff = std::max( 0, m_fpsLimitFrametime.load() - frametime );
       delay = std::max( delay, frametimeDiff );
-      delay = std::max( 0, std::min( delay, 20000 ) );
+      int32_t maxDelay = std::max( m_fpsLimitFrametime.load(), 20000 );
+      delay = std::max( 0, std::min( delay, maxDelay ) );
 
       Sleep::TimePoint nextStart = t + microseconds(delay);
       Sleep::sleepUntil( t, nextStart );

src/dxvk/framepacer/dxvk_framepacer_mode_min_latency.h

@@ -28,7 +28,8 @@ namespace dxvk {
         now - m_lastStart ).count();
       int32_t frametimeDiff = std::max( 0, m_fpsLimitFrametime.load() - frametime );
       int32_t delay = std::max( 0, frametimeDiff );
-      delay = std::min( delay, 20000 );
+      int32_t maxDelay = std::max( m_fpsLimitFrametime.load(), 20000 );
+      delay = std::min( delay, maxDelay );
 
       Sleep::TimePoint nextStart = now + std::chrono::microseconds(delay);
       Sleep::sleepUntil( now, nextStart );

src/util/util_fps_limiter.cpp

@@ -57,6 +57,8 @@ namespace dxvk {
       return;
     }
 
+    m_isActive.store(false);
+
     std::unique_lock<dxvk::mutex> lock(m_mutex);
     auto interval = m_targetInterval;
     auto latency = m_maxLatency;
@@ -79,7 +81,6 @@ namespace dxvk {
     // that can be written by setTargetFrameRate
     lock.unlock();
 
-    m_isActive.store(false);
     if (t1 < m_nextFrame) {
       m_isActive.store(true);
       Sleep::sleepUntil(t1, m_nextFrame);