Actually fix the race condition

src/citra_qt/configuration/config.cpp

@@ -404,7 +404,7 @@ void Config::SaveValues() {
 
     qt_config->beginGroup("Layout");
     WriteSetting("toggle_3d", Settings::values.toggle_3d, false);
-    WriteSetting("factor_3d", Settings::values.factor_3d, 0);
+    WriteSetting("factor_3d", Settings::values.factor_3d.load(), 0);
     WriteSetting("layout_option", static_cast<int>(Settings::values.layout_option));
     WriteSetting("swap_screen", Settings::values.swap_screen, false);
     WriteSetting("custom_layout", Settings::values.custom_layout, false);

src/core/hle/service/hid/hid.cpp

@@ -163,8 +163,7 @@ void Module::UpdatePadCallback(u64 userdata, s64 cycles_late) {
 
     // TODO(xperia64): How the 3D Slider is updated by the HID module needs to be RE'd
     // and possibly moved to its own Core::Timing event.
-    system.Kernel().GetSharedPageHandler().Set3DSlider(
-        Settings::values.toggle_3d ? Settings::values.factor_3d / 100.0f : 0.0f);
+    system.Kernel().GetSharedPageHandler().Set3DSlider(Settings::values.factor_3d / 100.0f);
 
     // Reschedule recurrent event
     system.CoreTiming().ScheduleEvent(pad_update_ticks - cycles_late, pad_update_event);

src/core/settings.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <array>
+#include <atomic>
 #include <string>
 #include <unordered_map>
 #include "common/common_types.h"
@@ -148,7 +149,7 @@ struct Values {
     float bg_blue;
 
     bool toggle_3d;
-    u8 factor_3d;
+    std::atomic<u8> factor_3d;
 
     // Audio
     bool enable_dsp_lle;

src/core/telemetry_session.cpp

@@ -179,7 +179,8 @@ TelemetrySession::TelemetrySession() {
              Settings::values.use_shader_jit);
     AddField(Telemetry::FieldType::UserConfig, "Renderer_UseVsync", Settings::values.use_vsync);
     AddField(Telemetry::FieldType::UserConfig, "Renderer_Toggle3d", Settings::values.toggle_3d);
-    AddField(Telemetry::FieldType::UserConfig, "Renderer_Factor3d", Settings::values.factor_3d);
+    AddField(Telemetry::FieldType::UserConfig, "Renderer_Factor3d",
+             Settings::values.factor_3d.load());
     AddField(Telemetry::FieldType::UserConfig, "System_IsNew3ds", Settings::values.is_new_3ds);
     AddField(Telemetry::FieldType::UserConfig, "System_RegionValue", Settings::values.region_value);
 }