OpenCL create subdevices CL_DEVICE_PARTITION_FAILED

问题

I'm stuck at getting clCreateSubDevices working, where CL_DEVICE_PARTITION_FAILED is always returned and I have no clue to solve this problem. I'm trying to create a subdevice with one core only. Here is the code, do you see anything wrong with it? Thanks!

Here are the function signatures: clCreateSubDevices, clGetPlatformIDs, clGetDeviceIDs

cl_platform_id platform_id = NULL;
cl_device_id device_id = NULL;
cl_uint ret_num_devices;
cl_uint ret_num_platforms;
cl_int ret = clGetPlatformIDs(1, &platform_id, &ret_num_platforms);
ret = clGetDeviceIDs( platform_id, CL_DEVICE_TYPE_GPU, 1,
                     &device_id, &ret_num_devices);

if (device_id == NULL) {
    fprintf(stderr, "failed to get device id!");
    return 1;
}

const cl_device_partition_property properties[3] = {
    CL_DEVICE_PARTITION_BY_COUNTS,
    1, // Use only one compute unit
    CL_DEVICE_PARTITION_BY_COUNTS_LIST_END
};

cl_device_id subdevice_id;
cl_int error = clCreateSubDevices(device_id, properties, 1, &subdevice_id, NULL);
if (error != CL_SUCCESS) {
    fprintf(stderr, "failed to create sub device %d!\n", error);
    return 1;
}

来源：https://stackoverflow.com/questions/27526963/opencl-create-subdevices-cl-device-partition-failed