From f42f59d68528f426bcafc77893ebc92ae00f5acc Mon Sep 17 00:00:00 2001
From: Kenneth Moreland <morelandkd@ornl.gov>
Date: Fri, 3 May 2024 17:03:20 -0400
Subject: [PATCH] Fix crash when CUDA device is disabled

There was an issue where if VTK-m was compiled with CUDA support but then
run on a computer where no CUDA device was available, an inappropriate
exception was thrown (instead of just disabling the device). The
initialization code should now properly check for the existance of a CUDA
device.
---
 docs/changelog/safe-cuda-runtime-config.md    |  7 +++++
 .../internal/RuntimeDeviceConfigurationCuda.h | 28 +++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)
 create mode 100644 docs/changelog/safe-cuda-runtime-config.md

diff --git a/docs/changelog/safe-cuda-runtime-config.md b/docs/changelog/safe-cuda-runtime-config.md
new file mode 100644
index 000000000..a9a0880cc
--- /dev/null
+++ b/docs/changelog/safe-cuda-runtime-config.md
@@ -0,0 +1,7 @@
+# Fix crash when CUDA device is disabled
+
+There was an issue where if VTK-m was compiled with CUDA support but then
+run on a computer where no CUDA device was available, an inappropriate
+exception was thrown (instead of just disabling the device). The
+initialization code should now properly check for the existance of a CUDA
+device.
diff --git a/vtkm/cont/cuda/internal/RuntimeDeviceConfigurationCuda.h b/vtkm/cont/cuda/internal/RuntimeDeviceConfigurationCuda.h
index 0e589a260..afd4505ca 100644
--- a/vtkm/cont/cuda/internal/RuntimeDeviceConfigurationCuda.h
+++ b/vtkm/cont/cuda/internal/RuntimeDeviceConfigurationCuda.h
@@ -10,6 +10,7 @@
 #ifndef vtk_m_cont_cuda_internal_RuntimeDeviceConfigurationCuda_h
 #define vtk_m_cont_cuda_internal_RuntimeDeviceConfigurationCuda_h
 
+#include <vtkm/cont/cuda/internal/DeviceAdapterRuntimeDetectorCuda.h>
 #include <vtkm/cont/cuda/internal/DeviceAdapterTagCuda.h>
 #include <vtkm/cont/internal/RuntimeDeviceConfiguration.h>
 
@@ -36,13 +37,28 @@ class RuntimeDeviceConfiguration<vtkm::cont::DeviceAdapterTagCuda>
 public:
   RuntimeDeviceConfiguration<vtkm::cont::DeviceAdapterTagCuda>()
   {
-    int tmp;
-    VTKM_CUDA_CALL(cudaGetDeviceCount(&tmp));
-    this->CudaDeviceCount = tmp;
-    this->CudaProp.resize(this->CudaDeviceCount);
-    for (int i = 0; i < this->CudaDeviceCount; ++i)
+    this->CudaDeviceCount = 0;
+    this->CudaProp.clear();
+    vtkm::cont::DeviceAdapterRuntimeDetector<vtkm::cont::DeviceAdapterTagCuda> detector;
+    if (detector.Exists())
     {
-      VTKM_CUDA_CALL(cudaGetDeviceProperties(&this->CudaProp[i], i));
+      try
+      {
+        int tmp;
+        VTKM_CUDA_CALL(cudaGetDeviceCount(&tmp));
+        this->CudaDeviceCount = tmp;
+        this->CudaProp.resize(this->CudaDeviceCount);
+        for (int i = 0; i < this->CudaDeviceCount; ++i)
+        {
+          VTKM_CUDA_CALL(cudaGetDeviceProperties(&this->CudaProp[i], i));
+        }
+      }
+      catch (...)
+      {
+        VTKM_LOG_F(vtkm::cont::LogLevel::Error,
+                   "Error retrieving CUDA device information. Disabling.");
+        this->CudaDeviceCount = 0;
+      }
     }
   }