[video_core] cpu buffer fix + kepler uploads / maxwell macro dirty tracking fixes (#4473)

- [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.

-------------------

Aimed to fix two known UE5 crashes: Kepler uploads and Maxwell macros, both caused by CPU/GPU races due dirty tracking issues.

Kepler ComputeInline: preserved dirty tracking across dma continuations and async readback.
Maxwell macros: preserved gpu owned subranges during page granular cpu uploads.
DiscardWrite: stopped clearing neighboring macro arguments by rounding up ranges.
DMA Step: improved continuation aware dirty sampling.

To the Ender Magnolia crew (maybe 1 or 2 persons): This will fix the dash crash, and the random / shackled beast vaper crashes.

There are some more UE5 issues to go next.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/4473
Reviewed-by: lizzie <lizzie@eden-emu.dev>
Reviewed-by: MaranBr <maranbr@eden-emu.dev>

1 files changed, 10 insertions, 5 deletions

diff --git a/src/video_core/dma_pusher.cpp b/src/video_core/dma_pusher.cpp
index 2417659f09..2c0ba007ef 100644
--- a/src/video_core/dma_pusher.cpp
+++ b/src/video_core/dma_pusher.cpp
@@ -16,7 +16,7 @@
 namespace Tegra {
 
 constexpr u32 MacroRegistersStart = 0xE00;
-[[maybe_unused]] constexpr u32 ComputeInline = 0x6D;
+constexpr u32 ComputeInline = 0x6D;
 
 DmaPusher::DmaPusher(Core::System& system_, MemoryManager& memory_manager_, Control::ChannelState& channel_state_)
     : system{system_}
@@ -73,11 +73,16 @@ bool DmaPusher::Step() {
         synced = false;
     }
 
-    if (header.size > 0 && dma_state.method >= MacroRegistersStart && subchannels[dma_state.subchannel]) {
-        subchannels[dma_state.subchannel]->current_dirty = memory_manager.IsMemoryDirty(dma_state.dma_get, header.size * sizeof(u32));
-    }
-
     if (header.size > 0) {
+        if (subchannels[dma_state.subchannel] && dma_state.method_count) {
+            const auto engine = subchannel_type[dma_state.subchannel];
+            const bool kepler_payload = engine == Engines::EngineTypes::KeplerCompute && dma_state.method == ComputeInline && dma_state.non_incrementing;
+            const bool macro_payload = engine == Engines::EngineTypes::Maxwell3D && dma_state.method >= MacroRegistersStart;
+            if (kepler_payload || macro_payload) {
+                const size_t words = std::min<size_t>(dma_state.method_count, header.size);
+                subchannels[dma_state.subchannel]->current_dirty = memory_manager.IsMemoryDirty(dma_state.dma_get, words * sizeof(u32));
+            }
+        }
         const bool use_safe = Settings::IsDMALevelDefault() ? Settings::IsGPULevelHigh() : Settings::IsDMALevelSafe();
         if (use_safe) {
             Tegra::Memory::GpuGuestMemory<Tegra::CommandHeader, Tegra::Memory::GuestMemoryFlags::SafeRead>headers(memory_manager, dma_state.dma_get, header.size, &command_headers);