From 9676add96873888bf2bb3a4978d3b981a95155ed Mon Sep 17 00:00:00 2001
From: Oleksandr Kuvshynov <661042+okuvshynov@users.noreply.github.com>
Date: Fri, 30 Jan 2026 21:12:05 -0500
Subject: [PATCH] vulkan: fix GPU deduplication logic.

As reported in https://github.com/ggml-org/llama.cpp/issues/19221, the
(same uuid, same driver) logic is problematic for windows+intel igpu.

Let's just avoid filtering for MoltenVK which is apple-specific, and
keep the logic the  same as before 88d23ad5 - just dedup based on UUID.

Verified that MacOS + 4xVega still reports 4 GPUs with this version.
---
 ggml/src/ggml-vulkan/ggml-vulkan.cpp | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/ggml/src/ggml-vulkan/ggml-vulkan.cpp b/ggml/src/ggml-vulkan/ggml-vulkan.cpp
index a99375c088..89e9ace263 100644
--- a/ggml/src/ggml-vulkan/ggml-vulkan.cpp
+++ b/ggml/src/ggml-vulkan/ggml-vulkan.cpp
@@ -5538,18 +5538,19 @@ static void ggml_vk_instance_init() {
                 // Check if there are two physical devices corresponding to the same GPU
                 // This handles the case where the same GPU appears with different drivers (e.g., RADV + AMDVLK on Linux),
                 // see https://github.com/ggml-org/llama.cpp/pull/7582 for original deduplication.
-                // However, for MoltenVK on macOS, multiple GPUs on the same card may report the same UUID,
-                // see https://github.com/KhronosGroup/MoltenVK/issues/2683. Until this is fixed, we'll only deduplicate
-                // when drivers differ (same driver + same UUID = likely different GPUs)
+                // MoltenVK on macOS may report the same UUID for distinct GPUs on multi-GPU cards,
+                // see https://github.com/KhronosGroup/MoltenVK/issues/2683. Skip dedup for MoltenVK.
                 auto old_device = std::find_if(
                     vk_instance.device_indices.begin(),
                     vk_instance.device_indices.end(),
                     [&devices, &new_id, &new_driver](const size_t k){
+                        if (new_driver.driverID == vk::DriverId::eMoltenvk) {
+                            return false;
+                        }
+
                         vk::PhysicalDeviceProperties2 old_props;
-                        vk::PhysicalDeviceDriverProperties old_driver;
                         vk::PhysicalDeviceIDProperties old_id;
-                        old_props.pNext = &old_driver;
-                        old_driver.pNext = &old_id;
+                        old_props.pNext = &old_id;
                         devices[k].getProperties2(&old_props);
 
                         bool same_uuid = std::equal(std::begin(old_id.deviceUUID), std::end(old_id.deviceUUID), std::begin(new_id.deviceUUID));
@@ -5558,10 +5559,7 @@ static void ggml_vk_instance_init() {
                             std::equal(std::begin(old_id.deviceLUID), std::end(old_id.deviceLUID), std::begin(new_id.deviceLUID))
                         );
 
-                        // Only deduplicate if same UUID AND different drivers
-                        // (same driver + same UUID on MoltenVK = likely different GPUs on multi-GPU card)
-                        bool different_driver = (old_driver.driverID != new_driver.driverID);
-                        return same_uuid && different_driver;
+                        return same_uuid;
                     }
                 );
                 if (old_device == vk_instance.device_indices.end()) {