Improve docs and exception-handling

Author: mdboom

cuda_core/cuda/core/system/_device.pyx

@@ -376,6 +376,15 @@ cdef class Device:
         -------
         cuda.core.Device
             The corresponding CUDA device.
+
+        Raises
+        ------
+        RuntimeError
+            No corresponding CUDA device is found for this NVML device.
+
+            For example, on a MIG system, the physical GPU will not have an
+            available CUDA device, since it can not be used directly, even
+            though it can be enumerated from NVML.
         """
         from cuda.core import Device as CudaDevice
 
@@ -890,8 +899,16 @@ cdef class Device:
     def pci_info(self) -> PciInfo:
         """
         :obj:`~_device.PciInfo` object with the PCI attributes of this device.
+
+        Non-physical devices, such as MIG devices, may not have PCI attributes.
+        In that case, this property will raise a `RuntimeError`.
         """
-        return PciInfo(nvml.device_get_pci_info_ext(self._handle), self._handle)
+        try:
+            pci_info = nvml.device_get_pci_info_ext(self._handle)
+        except nvml.InvalidArgumentError:
+            raise RuntimeError("This device does not have PCI attributes") from None
+        else:
+            return PciInfo(pci_info, self._handle)
 
     ##########################################################################
     # PERFORMANCE

cuda_core/tests/test_device.py

@@ -48,7 +48,7 @@ def test_to_system_device(deinit_cuda):
     # CUDA only returns a 2-byte PCI bus ID domain, whereas NVML returns a
     # 4-byte domain
     # MIG devices don't have pci_info, so skip the bus ID check if it's missing
-    with contextlib.suppress(_system.InvalidArgumentError):
+    with contextlib.suppress(RuntimeError):
         assert device.pci_bus_id == system_device.pci_info.bus_id[4:]