From b5b6f24d5bd3e1b8bb2cb5399b060bf97b964613 Mon Sep 17 00:00:00 2001
From: jpark37 <jpark37@users.noreply.github.com>
Date: Thu, 19 Dec 2019 10:00:59 -0800
Subject: [PATCH] libobs-d3d11: Increase the frame queue capacity

Sometimes Present stalls are seen when multiple swap chains are active.
This seems to fix that.
---
 libobs-d3d11/d3d11-subsystem.cpp | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/libobs-d3d11/d3d11-subsystem.cpp b/libobs-d3d11/d3d11-subsystem.cpp
index 4a5012b4b..f3724dfed 100644
--- a/libobs-d3d11/d3d11-subsystem.cpp
+++ b/libobs-d3d11/d3d11-subsystem.cpp
@@ -380,6 +380,25 @@ try {
 	return false;
 }
 
+static bool increase_maximum_frame_latency(ID3D11Device *device)
+{
+	ComQIPtr<IDXGIDevice1> dxgiDevice(device);
+	if (!dxgiDevice) {
+		blog(LOG_DEBUG, "%s: Failed to get IDXGIDevice1", __FUNCTION__);
+		return false;
+	}
+
+	const HRESULT hr = dxgiDevice->SetMaximumFrameLatency(16);
+	if (FAILED(hr)) {
+		blog(LOG_DEBUG, "%s: SetMaximumFrameLatency failed",
+		     __FUNCTION__);
+		return false;
+	}
+
+	blog(LOG_INFO, "DXGI increase maximum frame latency success");
+	return true;
+}
+
 #if USE_GPU_PRIORITY
 static bool set_priority(ID3D11Device *device)
 {
@@ -467,7 +486,12 @@ void gs_device::InitDevice(uint32_t adapterIdx)
 	blog(LOG_INFO, "D3D11 loaded successfully, feature level used: %x",
 	     (unsigned int)levelUsed);
 
-	/* adjust gpu thread priority on non-intel GPUs*/
+	/* prevent stalls sometimes seen in Present calls */
+	if (!increase_maximum_frame_latency(device)) {
+		blog(LOG_INFO, "DXGI increase maximum frame latency failed");
+	}
+
+	/* adjust gpu thread priority on non-intel GPUs */
 #if USE_GPU_PRIORITY
 	if (desc.VendorId != 0x8086 && !set_priority(device)) {
 		blog(LOG_INFO, "D3D11 GPU priority setup "