[dxvk] Add option to disable VK_NV_low_latency2

dxvk.conf

@@ -106,6 +106,15 @@
 # dxvk.latencyTolerance = 1000
 
 
+# Disables the use of VK_NV_low_latency2. This will make Reflex unavailable
+# in games, and if dxvk.latencySleep is set to True, a custom algorithm will
+# be used for latency control.
+#
+# Supported values: True, False
+
+# dxvk.disableNvLowLatency2 = False
+
+
 # Override PCI vendor and device IDs reported to the application. Can
 # cause the app to adjust behaviour depending on the selected values.
 #

src/dxvk/dxvk_adapter.cpp

@@ -293,6 +293,10 @@ namespace dxvk {
       enabledFeatures.vk12.bufferDeviceAddress = VK_TRUE;
     }
 
+    // Disable NV_low_latency2 if allowed via config
+    if (instance->options().disableNvLowLatency2)
+      devExtensions.nvLowLatency2.setMode(DxvkExtMode::Disabled);
+
     // If we don't have pageable device memory support, at least use
     // the legacy AMD extension to ensure we can oversubscribe VRAM
     if (!m_deviceExtensions.supports(devExtensions.extPageableDeviceLocalMemory.name()))

src/dxvk/dxvk_options.cpp

@@ -14,6 +14,7 @@ namespace dxvk {
     tearFree              = config.getOption<Tristate>("dxvk.tearFree",               Tristate::Auto);
     latencySleep          = config.getOption<Tristate>("dxvk.latencySleep",           Tristate::Auto);
     latencyTolerance      = config.getOption<int32_t> ("dxvk.latencyTolerance",       1000);
+    disableNvLowLatency2  = config.getOption<bool>    ("dxvk.disableNvLowLatency2",   false);
     hideIntegratedGraphics = config.getOption<bool>   ("dxvk.hideIntegratedGraphics", false);
     zeroMappedMemory      = config.getOption<bool>    ("dxvk.zeroMappedMemory",       false);
     allowFse              = config.getOption<bool>    ("dxvk.allowFse",               false);

src/dxvk/dxvk_options.h

@@ -43,6 +43,9 @@ namespace dxvk {
     /// Latency tolerance, in microseconds
     int32_t latencyTolerance = 0u;
 
+    /// Disable VK_NV_low_latency2
+    bool disableNvLowLatency2 = false;
+
     // Hides integrated GPUs if dedicated GPUs are
     // present. May be necessary for some games that
     // incorrectly assume monitor layouts.