From aecfa95b3b73f086164d8bc01da254ae5bfe08df Mon Sep 17 00:00:00 2001
From: Lester Hedges <lester.hedges@gmail.com>
Date: Wed, 4 Mar 2026 09:26:13 +0000
Subject: [PATCH] Handle missing OpenCL ICD loader during GPU platform
 detection.

---
 src/somd2/runner/_repex.py | 61 +++++++++++++++++++++++---------------
 1 file changed, 37 insertions(+), 24 deletions(-)

diff --git a/src/somd2/runner/_repex.py b/src/somd2/runner/_repex.py
index cdc1851..f6ba67b 100644
--- a/src/somd2/runner/_repex.py
+++ b/src/somd2/runner/_repex.py
@@ -575,46 +575,59 @@ def _check_device_memory(device_index=0):
         index: int
             The index of the GPU device.
         """
-        import pyopencl as cl
 
-        # Get the device.
-        platforms = cl.get_platforms()
-        all_devices = []
-        for platform in platforms:
-            try:
-                devices = platform.get_devices(device_type=cl.device_type.GPU)
-                all_devices.extend(devices)
-            except:
-                continue
-
-        if device_index >= len(all_devices):
-            msg = f"Device index {device_index} out of range. Found {len(all_devices)} GPU(s)."
-            _logger.error(msg)
-            raise IndexError(msg)
+        # Try to use pyopencl to detect the GPU vendor.
+        vendor = None
+        ocl_device = None
+        try:
+            import pyopencl as cl
 
-        device = all_devices[device_index]
-        total = device.global_mem_size
+            platforms = cl.get_platforms()
+            all_devices = []
+            for platform in platforms:
+                try:
+                    devices = platform.get_devices(device_type=cl.device_type.GPU)
+                    all_devices.extend(devices)
+                except Exception:
+                    continue
+
+            if device_index < len(all_devices):
+                ocl_device = all_devices[device_index]
+                vendor = ocl_device.vendor
+            else:
+                msg = f"Device index {device_index} out of range. Found {len(all_devices)} GPU(s)."
+                _logger.error(msg)
+                raise IndexError(msg)
+        except IndexError:
+            raise
+        except Exception:
+            _logger.warning(
+                "Could not query GPU platform via OpenCL; falling back to pynvml for NVIDIA detection."
+            )
 
-        # NVIDIA: Use pynvml
-        if "NVIDIA" in device.vendor:
+        # NVIDIA: Use pynvml (also used as fallback when OpenCL is unavailable).
+        if vendor is None or "NVIDIA" in vendor:
             try:
                 import pynvml
 
                 pynvml.nvmlInit()
-
                 handle = pynvml.nvmlDeviceGetHandleByIndex(device_index)
                 memory = pynvml.nvmlDeviceGetMemoryInfo(handle)
                 pynvml.nvmlShutdown()
                 return (memory.used, memory.free, memory.total)
             except Exception as e:
-                msg = f"Could not get NVIDIA GPU memory info for device {device_index}: {e}"
+                if vendor is None:
+                    msg = f"Could not get GPU memory info for device {device_index} via OpenCL or pynvml: {e}"
+                else:
+                    msg = f"Could not get NVIDIA GPU memory info for device {device_index}: {e}"
                 _logger.error(msg)
                 raise RuntimeError(msg) from e
 
-        # AMD: Use OpenCL extension
-        elif "AMD" in device.vendor or "Advanced Micro Devices" in device.vendor:
+        # AMD: Use OpenCL extension.
+        elif "AMD" in vendor or "Advanced Micro Devices" in vendor:
             try:
-                free_memory_info = device.get_info(0x4038)
+                total = ocl_device.global_mem_size
+                free_memory_info = ocl_device.get_info(0x4038)
                 free_kb = (
                     free_memory_info[0]
                     if isinstance(free_memory_info, list)