From 39b9892f000b3ae943d3dd72a8729eaf71db0595 Mon Sep 17 00:00:00 2001
From: Takoroka <137927095+Takoroka@users.noreply.github.com>
Date: Sun, 1 Nov 2026 01:49:31 -0400
Subject: vulkan_device: keep an integrated GPU's budget within its memory
 share

CollectPhysicalMemoryInfo gives an integrated GPU 4 GiB of device memory
(6 GiB with aggressive VRAM use), since its device-local heap is system
memory. GetDeviceMemoryBudget returned the heap's driver budget instead
(21178 MiB on a Radeon 780M), and the texture cache follows that budget
for Switch 2 titles: it collected only past 20.6 GB, filling system RAM,
and kept ASTC uncompressed (the BC3 switch looks at the budget too). Cap
it at that share.

Radeon 780M, Mario Kart World title screen, 200 s: shared GPU memory
2.7 -> 3.6 GB instead of 7.6 -> 12.7 GB (0.25 instead of 1.8 GB/min),
private bytes 12.9 instead of 22.4 GB at the end, ASTC re-compressed to
BC3, same frame rate.
---
 src/video_core/vulkan_common/vulkan_device.cpp | 7 +++++++
 1 file changed, 7 insertions(+)

(limited to 'src/video_core/vulkan_common/vulkan_device.cpp')

diff --git a/src/video_core/vulkan_common/vulkan_device.cpp b/src/video_core/vulkan_common/vulkan_device.cpp
index 623ab7c30d..c1a40e7906 100644
--- a/src/video_core/vulkan_common/vulkan_device.cpp
+++ b/src/video_core/vulkan_common/vulkan_device.cpp
@@ -1663,6 +1663,13 @@ u64 Device::GetDeviceMemoryBudget() const {
             result += AllocatedUsage(budget.heapUsage[heap], heap_budgets[heap]);
         }
     }
+    if (is_integrated) {
+        // An integrated GPU's device-local heap is system memory (a Radeon 780M reported a 21 GB
+        // budget): following it let the texture cache fill that much RAM before collecting, and
+        // kept ASTC uncompressed. Its budget is at most the share CollectPhysicalMemoryInfo
+        // gives it (4 GiB, 6 GiB with aggressive VRAM use).
+        result = (std::min)(result, device_access_memory);
+    }
     return result;
 }
 
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