From 8074560e8a66ed1b221b867c443bd577de66555f Mon Sep 17 00:00:00 2001
From: Mateusz Hoppe <mateusz.hoppe@intel.com>
Date: Fri, 12 Sep 2025 14:38:05 +0000
Subject: [PATCH] fix: return 0 as PARTITION MAX SUBDEVICES in expose single
 device mode

Related-To: NEO-16116

Signed-off-by: Mateusz Hoppe <mateusz.hoppe@intel.com>
---
 opencl/source/cl_device/cl_device_caps.cpp    |  4 +++-
 .../api/cl_create_sub_devices_tests.inl       | 21 +++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/opencl/source/cl_device/cl_device_caps.cpp b/opencl/source/cl_device/cl_device_caps.cpp
index 88a26deca9..521d3ad04c 100644
--- a/opencl/source/cl_device/cl_device_caps.cpp
+++ b/opencl/source/cl_device/cl_device_caps.cpp
@@ -222,7 +222,9 @@ void ClDevice::initializeCaps() {
     deviceInfo.deviceAvailable = CL_TRUE;
     deviceInfo.compilerAvailable = CL_TRUE;
     deviceInfo.parentDevice = nullptr;
-    deviceInfo.partitionMaxSubDevices = device.getNumSubDevices();
+    if (!rootDeviceEnvironment.isExposeSingleDeviceMode()) {
+        deviceInfo.partitionMaxSubDevices = device.getNumSubDevices();
+    }
     if (deviceInfo.partitionMaxSubDevices > 0) {
         deviceInfo.partitionProperties[0] = CL_DEVICE_PARTITION_BY_AFFINITY_DOMAIN;
         deviceInfo.partitionProperties[1] = 0;
diff --git a/opencl/test/unit_test/api/cl_create_sub_devices_tests.inl b/opencl/test/unit_test/api/cl_create_sub_devices_tests.inl
index 0e65a53f06..a4444d20ff 100644
--- a/opencl/test/unit_test/api/cl_create_sub_devices_tests.inl
+++ b/opencl/test/unit_test/api/cl_create_sub_devices_tests.inl
@@ -11,6 +11,7 @@
 #include "shared/test/common/test_macros/test.h"
 
 #include "opencl/source/api/api.h"
+#include "opencl/source/cl_device/cl_device_get_cap.inl"
 
 #include <memory>
 
@@ -175,6 +176,26 @@ TEST_F(ClCreateSubDevicesTests, GivenExposeSingleDeviceModeWhenCreatingSubDevice
     EXPECT_EQ(CL_DEVICE_PARTITION_FAILED, retVal);
 }
 
+TEST_F(ClCreateSubDevicesTests, GivenExposeSingleDeviceModeWhenQueryingDeviceCapsThenPartitionMaxSubdevicesReturnsZero) {
+    debugManager.flags.CreateMultipleSubDevices.set(2);
+    mockDeviceCreateSingleDeviceBackup = false;
+
+    auto executionEnvironment = MockDevice::prepareExecutionEnvironment(defaultHwInfo.get(), 0);
+    for (auto rootDeviceIndex = 0u; rootDeviceIndex < executionEnvironment->rootDeviceEnvironments.size(); rootDeviceIndex++) {
+        executionEnvironment->rootDeviceEnvironments[rootDeviceIndex]->setExposeSingleDeviceMode(true);
+    }
+
+    device = std::make_unique<MockClDevice>(NEO::MockDevice::createWithExecutionEnvironment<NEO::MockDevice>(defaultHwInfo.get(), executionEnvironment, 0));
+    size_t size = sizeof(uint32_t);
+    const void *cap = nullptr;
+    device->getCap<CL_DEVICE_PARTITION_MAX_SUB_DEVICES>(cap, size, size);
+
+    auto *partitionMaxSubDevices = reinterpret_cast<const uint32_t *>(cap);
+
+    EXPECT_EQ(0u, *partitionMaxSubDevices);
+    EXPECT_EQ(0u, device->getDeviceInfo().partitionMaxSubDevices);
+}
+
 TEST_F(ClCreateSubDevicesTests, GivenExposeSingleDeviceModeAndFlatHierarchyWhenCreatingSubDevicesThenErrorIsReturned) {
     std::unordered_map<std::string, std::string> mockableEnvs = {{"ZE_FLAT_DEVICE_HIERARCHY", "FLAT"}};
     VariableBackup<std::unordered_map<std::string, std::string> *> mockableEnvValuesBackup(&IoFunctions::mockableEnvValues, &mockableEnvs);