[settings] add PR4490 & PR4492 toggles (#4502)

- [X] I have read and followed the [Contribution Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/CONTRIBUTING.md#code-contributions).
- [X] I have read and followed the [AI Policy](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/AI.md)
- [X] I have read and followed the [Coding Guidelines](https://git.eden-emu.dev/eden-emu/eden/src/branch/master/docs/policies/Coding.md) to the best of my ability.

-------------------
TEMPORARY! Pushed under Camille's instruction. Will be dropped as soon as they get optimized.
Aimed to avoid reported perf impact from PRs 4490 and 4492 on 30-sep-2026 nightly,

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4502
Reviewed-by: MaranBr <maranbr@eden-emu.dev>
Reviewed-by: CamilleLaVey <camillelavey99@gmail.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/src/video_core/gpu.cpp b/src/video_core/gpu.cpp
index 6aa7f9abd8..4e36d086e6 100644
--- a/src/video_core/gpu.cpp
+++ b/src/video_core/gpu.cpp
@@ -227,15 +227,17 @@ struct GPU::Impl {
 
     /// Notify rasterizer that any caches of the specified region should be invalidated
     void InvalidateRegion(DAddr addr, u64 size, bool preserve_gpu_writes) {
-        VideoCore::RasterizerInterface* rasterizer = renderer->ReadRasterizer();
-        if (preserve_gpu_writes && rasterizer->MustFlushRegion(addr, size, VideoCommon::CacheType::BufferCache)) {
-            const u64 fence = RequestSyncOperation([rasterizer, addr, size] {
-                rasterizer->FlushRegion(addr, size, VideoCommon::CacheType::BufferCache);
-                rasterizer->OnCacheInvalidation(addr, size);
-            });
-            gpu_thread.TickGPU(is_async);
-            WaitForSyncOperation(fence);
-            return;
+        if (Settings::values.nce_invalidation_gpu_readback.GetValue()) {
+            VideoCore::RasterizerInterface* rasterizer = renderer->ReadRasterizer();
+            if (preserve_gpu_writes && rasterizer->MustFlushRegion(addr, size, VideoCommon::CacheType::BufferCache)) {
+                const u64 fence = RequestSyncOperation([rasterizer, addr, size] {
+                    rasterizer->FlushRegion(addr, size, VideoCommon::CacheType::BufferCache);
+                    rasterizer->OnCacheInvalidation(addr, size);
+                });
+                gpu_thread.TickGPU(is_async);
+                WaitForSyncOperation(fence);
+                return;
+            }
         }
         gpu_thread.InvalidateRegion(addr, size);
     }