From b13b7010b9fb31a742ae0f52197284c2783063ef Mon Sep 17 00:00:00 2001
From: Soumith Chintala <soumith@gmail.com>
Date: Fri, 31 Mar 2017 12:19:59 -0400
Subject: [PATCH] check for nvidia driver's sufficiency before checking for
 number of CUDA devices (#1156)

---
 torch/csrc/autograd/engine.cpp | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/torch/csrc/autograd/engine.cpp b/torch/csrc/autograd/engine.cpp
index 4c025631f2fbc..3f7c6f897b977 100644
--- a/torch/csrc/autograd/engine.cpp
+++ b/torch/csrc/autograd/engine.cpp
@@ -350,7 +350,14 @@ auto Engine::ready_queue(int device) -> ReadyQueue& {
 auto Engine::start_threads() -> void {
   int num_devices = 0;
 #ifdef WITH_CUDA
-  THCudaCheck(cudaGetDeviceCount(&num_devices));
+  cudaError_t err = cudaGetDeviceCount(&num_devices);
+
+  // check for case of compiled with CUDA but no NVIDIA driver available
+  if (err == cudaErrorInsufficientDriver) {
+    num_devices = 0;
+  } else {
+    THCudaCheck(err);
+  }
 #endif
   ready_queues = std::vector<std::unique_ptr<ReadyQueue>>(num_devices + 1);
   for (auto& queue : ready_queues) {