From fce9c5fd25c66558eb8ed4e9e5ca9129589a5e7d Mon Sep 17 00:00:00 2001
From: Takoroka <137927095+Takoroka@users.noreply.github.com>
Date: Sun, 1 Nov 2026 02:08:04 -0500
Subject: vulkan_device: tell AMD GCN4 apart before float16 is turned off

AMD GCN4 and older are recognised by their lack of float16. Since float16
is turned off for every non-Mesa AMD driver (2026+ versions break it),
the sampler min/max check that runs after that saw every AMD GPU as GCN4
and removed VK_EXT_sampler_filter_minmax: a Radeon 780M (RDNA3) logged
"AMD GCN4 and earlier have broken VK_EXT_sampler_filter_minmax", and
samplers with a min/max reduction fell back to plain filtering there.
Read it once, before float16 is turned off.
---
 src/video_core/vulkan_common/vulkan_device.cpp | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

(limited to 'src/video_core')

diff --git a/src/video_core/vulkan_common/vulkan_device.cpp b/src/video_core/vulkan_common/vulkan_device.cpp
index c1a40e7906..b65c721bb8 100644
--- a/src/video_core/vulkan_common/vulkan_device.cpp
+++ b/src/video_core/vulkan_common/vulkan_device.cpp
@@ -620,12 +620,16 @@ Device::Device(VkInstance instance_, vk::PhysicalDevice physical_, VkSurfaceKHR
     }
 
     sets_per_pool = 64;
+    // AMD GCN4 and older are told apart by their lack of float16, read before float16 is turned
+    // off for newer AMD drivers below: checked after that, every AMD GPU looked like GCN4 and lost
+    // VK_EXT_sampler_filter_minmax (an RDNA3 Radeon 780M logged it).
+    const bool amd_gcn4_or_older = is_amd && !features.shader_float16_int8.shaderFloat16;
     if (is_amd_driver) {
         // AMD drivers need a higher amount of Sets per Pool in certain circumstances like in XC2.
         sets_per_pool = 96;
 
         // Disable VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT on AMD GCN4 and lower as it is broken.
-        if (!features.shader_float16_int8.shaderFloat16) {
+        if (amd_gcn4_or_older) {
             LOG_WARNING(Render_Vulkan,
                         "AMD GCN4 and earlier have broken VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT");
             has_broken_cube_compatibility = true;
@@ -641,7 +645,7 @@ Device::Device(VkInstance instance_, vk::PhysicalDevice physical_, VkSurfaceKHR
 
     if (extensions.sampler_filter_minmax && is_amd) {
         // Disable ext_sampler_filter_minmax on AMD GCN4 and lower as it is broken.
-        if (!features.shader_float16_int8.shaderFloat16) {
+        if (amd_gcn4_or_older) {
             LOG_WARNING(Render_Vulkan,
                         "AMD GCN4 and earlier have broken VK_EXT_sampler_filter_minmax");
             RemoveExtension(extensions.sampler_filter_minmax,
-- 
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