nx2: rearm clean read areas when the GPU writes them again

Port the coherency changes from alarok/Eglantine 77fc365f2 without its diagnostic framework or shutdown changes. Only GPU-dirty CPU reads become permanently preflushable, clean areas can be trapped on the next write, non-core readers avoid indexing core arrays, and collected CPU writes precede readback.

Assisted-by: Codex (source review, selective integration and verification)
(cherry picked from commit b64e211957180aa218ec6d9a3bcb020332279c3f)

1 files changed, 3 insertions, 1 deletions

diff --git a/src/video_core/gpu.cpp b/src/video_core/gpu.cpp
index 53f8f063f7..681a4a232d 100644
--- a/src/video_core/gpu.cpp
+++ b/src/video_core/gpu.cpp
@@ -228,7 +228,9 @@ struct GPU::Impl {
                      raster_area.start_address, raster_area.end_address,
                      reads.load(std::memory_order_relaxed));
         }
-        const u64 fence = RequestSyncOperation([this, &raster_area]() {
+        const u64 fence = RequestSyncOperation([this, raster_area]() {
+            // Apply collected guest writes before downloading GPU data over guest memory.
+            InvalidateGPUCache();
             renderer->ReadRasterizer()->FlushRegion(raster_area.start_address, raster_area.end_address - raster_area.start_address);
         });
         gpu_thread.TickGPU(is_async);