VideoCommon: Make Presenter aware of the next swap time to eliminate unsafe usage of GetTicks() with ImmediateXFB + DualCore.

Source/Core/VideoCommon/BPStructs.cpp

@@ -13,7 +13,6 @@
 #include "Common/EnumMap.h"
 #include "Common/Logging/Log.h"
 
-#include "Core/CoreTiming.h"
 #include "Core/DolphinAnalytics.h"
 #include "Core/FifoPlayer/FifoPlayer.h"
 #include "Core/FifoPlayer/FifoRecorder.h"
@@ -359,14 +358,8 @@ static void BPWritten(PixelShaderManager& pixel_shader_manager, XFStateManager&
 
       if (g_ActiveConfig.bImmediateXFB)
       {
-        // TODO: GetTicks is not sane from the GPU thread.
-        // This value is currently used for frame dumping and the custom shader "time_ms" value.
-        // Frame dumping has more calls that aren't sane from the GPU thread.
-        // i.e. Frame dumping is not sane in "Dual Core" mode in general.
-        const u64 ticks = system.GetCoreTiming().GetTicks();
-
         // below div two to convert from bytes to pixels - it expects width, not stride
-        g_presenter->ImmediateSwap(destAddr, destStride / 2, destStride, height, ticks);
+        g_presenter->ImmediateSwap(destAddr, destStride / 2, destStride, height);
       }
       else
       {

Source/Core/VideoCommon/FrameDumpFFMpeg.cpp

@@ -65,6 +65,7 @@ namespace
 {
 AVRational GetTimeBaseForCurrentRefreshRate(s64 max_denominator)
 {
+  // TODO: GetTargetRefreshRate* are not safe from GPU thread.
   auto& vi = Core::System::GetInstance().GetVideoInterface();
   int num;
   int den;
@@ -368,6 +369,7 @@ void FFMpegFrameDump::AddFrame(const FrameData& frame)
   // Calculate presentation timestamp from ticks since start.
   const s64 pts = av_rescale_q(
       frame.state.ticks - m_context->start_ticks,
+      // TODO: GetTicksPerSecond is not safe from GPU thread.
       AVRational{1, int(Core::System::GetInstance().GetSystemTimers().GetTicksPerSecond())},
       m_context->codec->time_base);
 

Source/Core/VideoCommon/Present.cpp

@@ -215,12 +215,14 @@ void Presenter::ViSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height,
   }
 }
 
-void Presenter::ImmediateSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height, u64 ticks)
+void Presenter::ImmediateSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height)
 {
+  const u64 ticks = m_next_swap_estimated_ticks;
+
   FetchXFB(xfb_addr, fb_width, fb_stride, fb_height, ticks);
 
   PresentInfo present_info;
-  present_info.emulated_timestamp = ticks;  // TODO: This should be the time of the next VI field
+  present_info.emulated_timestamp = ticks;
   present_info.frame_count = m_frame_count++;
   present_info.reason = PresentInfo::PresentReason::Immediate;
   present_info.present_count = m_present_count++;
@@ -235,6 +237,12 @@ void Presenter::ImmediateSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_
   video_events.after_present_event.Trigger(present_info);
 }
 
+void Presenter::SetNextSwapEstimatedTime(u64 ticks, TimePoint host_time)
+{
+  m_next_swap_estimated_ticks = ticks;
+  m_next_swap_estimated_time = host_time;
+}
+
 void Presenter::ProcessFrameDumping(u64 ticks) const
 {
   if (g_frame_dumper->IsFrameDumping() && m_xfb_entry)
@@ -938,8 +946,10 @@ void Presenter::DoState(PointerWrap& p)
     // This technically counts as the end of the frame
     GetVideoEvents().after_frame_event.Trigger(Core::System::GetInstance());
 
-    ImmediateSwap(m_last_xfb_addr, m_last_xfb_width, m_last_xfb_stride, m_last_xfb_height,
+    m_next_swap_estimated_ticks = m_last_xfb_ticks;
-                  m_last_xfb_ticks);
+    m_next_swap_estimated_time = Clock::now();
+
+    ImmediateSwap(m_last_xfb_addr, m_last_xfb_width, m_last_xfb_stride, m_last_xfb_height);
   }
 }
 

Source/Core/VideoCommon/Present.h

@@ -37,7 +37,9 @@ public:
 
   void ViSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height, u64 ticks,
               TimePoint presentation_time);
-  void ImmediateSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height, u64 ticks);
+  void ImmediateSwap(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height);
+
+  void SetNextSwapEstimatedTime(u64 ticks, TimePoint host_time);
 
   void Present(std::optional<TimePoint> presentation_time = std::nullopt);
   void ClearLastXfbId() { m_last_xfb_id = std::numeric_limits<u64>::max(); }
@@ -167,6 +169,11 @@ private:
   u32 m_last_xfb_height = MAX_XFB_HEIGHT;
 
   Common::EventHook m_config_changed;
+
+  // Calculated from the previous swap time and current refresh rate.
+  // Can be used for presentation of ImmediateXFB swaps which don't have timing information.
+  u64 m_next_swap_estimated_ticks = 0;
+  TimePoint m_next_swap_estimated_time{Clock::now()};
 };
 
 }  // namespace VideoCommon

Source/Core/VideoCommon/VideoBackendBase.cpp

@@ -21,6 +21,8 @@
 #include "Core/Core.h"
 #include "Core/CoreTiming.h"
 #include "Core/DolphinAnalytics.h"
+#include "Core/HW/SystemTimers.h"
+#include "Core/HW/VideoInterface.h"
 #include "Core/System.h"
 
 // TODO: ugly
@@ -93,16 +95,35 @@ std::string VideoBackendBase::BadShaderFilename(const char* shader_stage, int co
 void VideoBackendBase::Video_OutputXFB(u32 xfb_addr, u32 fb_width, u32 fb_stride, u32 fb_height,
                                        u64 ticks)
 {
-  if (m_initialized && g_presenter && !g_ActiveConfig.bImmediateXFB)
+  if (!m_initialized || !g_presenter)
+    return;
+
+  auto& system = Core::System::GetInstance();
+  auto& core_timing = system.GetCoreTiming();
+
+  if (!g_ActiveConfig.bImmediateXFB)
   {
-    auto& system = Core::System::GetInstance();
     system.GetFifo().SyncGPU(Fifo::SyncGPUReason::Swap);
 
-    const TimePoint presentation_time = system.GetCoreTiming().GetTargetHostTime(ticks);
+    const TimePoint presentation_time = core_timing.GetTargetHostTime(ticks);
     AsyncRequests::GetInstance()->PushEvent([=] {
       g_presenter->ViSwap(xfb_addr, fb_width, fb_stride, fb_height, ticks, presentation_time);
     });
   }
+
+  // Inform the Presenter of the next estimated swap time.
+
+  auto& vi = system.GetVideoInterface();
+  const s64 refresh_rate_den = vi.GetTargetRefreshRateDenominator();
+  const s64 refresh_rate_num = vi.GetTargetRefreshRateNumerator();
+
+  const auto next_swap_estimated_ticks =
+      ticks + (system.GetSystemTimers().GetTicksPerSecond() * refresh_rate_den / refresh_rate_num);
+  const auto next_swap_estimated_time = core_timing.GetTargetHostTime(next_swap_estimated_ticks);
+
+  AsyncRequests::GetInstance()->PushEvent([=] {
+    g_presenter->SetNextSwapEstimatedTime(next_swap_estimated_ticks, next_swap_estimated_time);
+  });
 }
 
 u32 VideoBackendBase::Video_GetQueryResult(PerfQueryType type)

Source/Core/VideoCommon/VideoEvents.h

@@ -34,7 +34,6 @@ struct PresentInfo
   PresentReason reason = PresentReason::Immediate;
 
   // The exact emulated time of the when real hardware would have presented this frame
-  // FIXME: Immediate should predict the timestamp of this present
   u64 emulated_timestamp = 0;
 
   // TODO: