Function _has_usable_nvidia_gpu

studio/install_python_stack.py:818–858

Return True when an NVIDIA GPU is present and usable. Primary probe: nvidia-smi -L (subprocess). Fallback: /proc/driver/nvidia/gpus/ sysfs (Linux only) -- handles the case where nvidia-smi is present but the subprocess fails (PATH gap, timeout, driver initialisation race). If either

()

def _has_usable_nvidia_gpu() -> bool:
    """Return True when an NVIDIA GPU is present and usable.

    Primary probe: nvidia-smi -L (subprocess).
    Fallback: /proc/driver/nvidia/gpus/ sysfs (Linux only) -- handles the
    case where nvidia-smi is present but the subprocess fails (PATH gap,
    timeout, driver initialisation race). If either probe confirms an
    NVIDIA GPU the function returns True so _has_rocm_gpu() is blocked.

    CUDA_VISIBLE_DEVICES set to "" or "-1" hides every NVIDIA device (mixed
    AMD+NVIDIA hosts steering work to the AMD card); neither probe honours
    that env var, so check it first and report the GPU as not usable. Unset
    means all devices visible.
    """
    cvd = os.environ.get("CUDA_VISIBLE_DEVICES")
    if cvd is not None and cvd.strip() in ("", "-1"):
        return False
    exe = shutil.which("nvidia-smi")
    if exe:
        try:
            result = subprocess.run(
                [exe, "-L"],
                stdout = subprocess.PIPE,
                stderr = subprocess.DEVNULL,
                text = True,
                timeout = 10,
            )
            if result.returncode == 0 and "GPU " in result.stdout:
                return True
        except Exception:
            pass
    # Fallback: the NVIDIA driver exposes one subdirectory per GPU under
    # /proc/driver/nvidia/gpus/ on Linux regardless of nvidia-smi state.
    if sys.platform != "win32":
        try:
            gpu_dir = "/proc/driver/nvidia/gpus"
            if os.path.isdir(gpu_dir) and os.listdir(gpu_dir):
                return True
        except OSError:
            pass
    return False


def _detect_amd_gfx_codes() -> list[str]: