From 68839943b34888a9840822347712c6dfed183ee8 Mon Sep 17 00:00:00 2001
From: Ribbit <ribbit@placeholder.com>
Date: Fri, 10 Oct 2025 22:08:44 -0700
Subject: [PATCH] [vk] Fix stock qualcomm driver regression

---
 src/video_core/buffer_cache/buffer_cache.h     | 18 ++++++++++++++++--
 .../buffer_cache/buffer_cache_base.h           |  2 ++
 .../renderer_vulkan/vk_buffer_cache.h          |  4 ++++
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/video_core/buffer_cache/buffer_cache.h b/src/video_core/buffer_cache/buffer_cache.h
index 9eaa322c9c..c47db2a0eb 100644
--- a/src/video_core/buffer_cache/buffer_cache.h
+++ b/src/video_core/buffer_cache/buffer_cache.h
@@ -790,9 +790,10 @@ void BufferCache<P>::BindHostGraphicsUniformBuffer(size_t stage, u32 index, u32
     const Binding& binding = channel_state->uniform_buffers[stage][index];
     const DAddr device_addr = binding.device_addr;
     const u32 size = (std::min)(binding.size, (*channel_state->uniform_buffer_sizes)[stage][index]);
+    const bool force_old_ubo = ForceOldUBOMethod();
     Buffer& buffer = slot_buffers[binding.buffer_id];
     TouchBuffer(buffer, binding.buffer_id);
-    const bool use_fast_buffer = binding.buffer_id != NULL_BUFFER_ID &&
+    const bool use_fast_buffer = !force_old_ubo && binding.buffer_id != NULL_BUFFER_ID &&
                                  size <= channel_state->uniform_buffer_skip_cache_size &&
                                  !memory_tracker.IsRegionGpuModified(device_addr, size);
     if (use_fast_buffer) {
@@ -848,7 +849,9 @@ void BufferCache<P>::BindHostGraphicsUniformBuffer(size_t stage, u32 index, u32
     } else {
         runtime.BindUniformBuffer(buffer, offset, size);
     }
-    channel_state->fast_bound_uniform_buffers[stage] &= ~(1u << binding_index);
+    if (!force_old_ubo) {
+        channel_state->fast_bound_uniform_buffers[stage] &= ~(1u << binding_index);
+    }
 }
 
 template <class P>
@@ -1781,8 +1784,19 @@ std::span<u8> BufferCache<P>::ImmediateBuffer(size_t wanted_capacity) {
     return std::span<u8>(immediate_buffer_alloc.data(), wanted_capacity);
 }
 
+template <class P>
+bool BufferCache<P>::ForceOldUBOMethod() const noexcept {
+    if constexpr (requires(const Runtime& r) { r.ForceOldUniformBufferMethod(); }) {
+        return runtime.ForceOldUniformBufferMethod();
+    }
+    return false;
+}
+
 template <class P>
 bool BufferCache<P>::HasFastUniformBufferBound(size_t stage, u32 binding_index) const noexcept {
+    if (ForceOldUBOMethod()) {
+        return false;
+    }
     return ((channel_state->fast_bound_uniform_buffers[stage] >> binding_index) & 1u) != 0;
 }
 
diff --git a/src/video_core/buffer_cache/buffer_cache_base.h b/src/video_core/buffer_cache/buffer_cache_base.h
index 1b551931a4..722930fe3e 100644
--- a/src/video_core/buffer_cache/buffer_cache_base.h
+++ b/src/video_core/buffer_cache/buffer_cache_base.h
@@ -449,6 +449,8 @@ private:
 
     [[nodiscard]] bool HasFastUniformBufferBound(size_t stage, u32 binding_index) const noexcept;
 
+    [[nodiscard]] bool ForceOldUBOMethod() const noexcept;
+
     void ClearDownload(DAddr base_addr, u64 size);
 
     void InlineMemoryImplementation(DAddr dest_address, size_t copy_size,
diff --git a/src/video_core/renderer_vulkan/vk_buffer_cache.h b/src/video_core/renderer_vulkan/vk_buffer_cache.h
index 86bce01596..b3a41d1149 100644
--- a/src/video_core/renderer_vulkan/vk_buffer_cache.h
+++ b/src/video_core/renderer_vulkan/vk_buffer_cache.h
@@ -94,6 +94,10 @@ public:
 
     bool CanReportMemoryUsage() const;
 
+    [[nodiscard]] bool ForceOldUniformBufferMethod() const noexcept {
+        return device.GetDriverID() == VK_DRIVER_ID_QUALCOMM_PROPRIETARY;
+    }
+
     u32 GetStorageBufferAlignment() const;
 
     [[nodiscard]] StagingBufferRef UploadStagingBuffer(size_t size);