From 847d7f21af18ed51fe96f7054191b4a36f90254c Mon Sep 17 00:00:00 2001
From: Nikita Shulga <nshulga@meta.com>
Date: Tue, 9 Sep 2025 04:12:10 +0000
Subject: [PATCH] [CUDA-13] Implement workaround for cudaErrorNotSupported
 (#162412)

See https://github.com/pytorch/pytorch/issues/162333#issuecomment-3267929585
Pull Request resolved: https://github.com/pytorch/pytorch/pull/162412
Approved by: https://github.com/eqy, https://github.com/atalman
---
 c10/cuda/CUDAFunctions.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/c10/cuda/CUDAFunctions.cpp b/c10/cuda/CUDAFunctions.cpp
index 683ed9b7684..9839e4e7204 100644
--- a/c10/cuda/CUDAFunctions.cpp
+++ b/c10/cuda/CUDAFunctions.cpp
@@ -78,6 +78,18 @@ int device_count_impl(bool fail_if_no_driver) {
           "would like to use GPUs, turn off ASAN.");
       break;
 #endif // C10_ASAN_ENABLED
+#if _WIN32 && CUDA_VERSION >= 13000
+    // Workaround for CUDA-13.0 error handling on Windows, see
+    // https://github.com/pytorch/pytorch/issues/162333#issuecomment-3267929585
+    case cudaErrorNotSupported:
+      if (!fail_if_no_driver) {
+        TORCH_WARN(
+            "cudaGetDeviceCount() returned cudaErrorNotSupported, "
+            "likely using older driver or on CPU machine");
+        count = 0;
+        break;
+      }
+#endif
     default:
       TORCH_CHECK(
           false,