update cuda docs

Author: sjpb

ansible/roles/cuda/README.md

@@ -1,15 +1,15 @@
 # cuda
 
-Install NVIDIA CUDA. The CUDA binaries are added to the PATH for all users, and the [NVIDIA persistence daemon](https://docs.nvidia.com/deploy/driver-persistence/index.html#persistence-daemon) is enabled.
+Install NVIDIA drivers and optionally CUDA packages. CUDA binaries are added to the `$PATH` for all users, and the [NVIDIA persistence daemon](https://docs.nvidia.com/deploy/driver-persistence/index.html#persistence-daemon) is enabled.
 
 ## Prerequisites
 
 Requires OFED to be installed to provide required kernel-* packages.
 
 ## Role Variables
 
-- `cuda_distro`: Optional. Default `rhel8`.
-- `cuda_repo`: Optional. Default `https://developer.download.nvidia.com/compute/cuda/repos/{{ cuda_distro }}/x86_64/cuda-{{ cuda_distro }}.repo`
-- `cuda_driver_stream`: Optional. The default value `default` will, on first use of this role, enable the dkms-flavour `nvidia-driver` DNF module stream with the current highest version number. The `latest-dkms` stream is not enabled, and subsequent runs of the role will *not* change the enabled stream, even if a later version has become available. Changing this value once an `nvidia-driver` stream has been enabled raises an error. If an upgrade of the `nvidia-driver` module is required, the currently-enabled stream and all packages should be manually removed.
+- `cuda_repo_url`: Optional. URL of `.repo` file. Default is upstream for appropriate OS/architecture.
+- `cuda_driver_stream`: Optional. Version of `nvidia-driver` stream to enable. This controls whether the open or proprietary drivers are installed and the major version. Changing this once the drivers are installed does not change the version.
 - `cuda_packages`: Optional. Default: `['cuda', 'nvidia-gds']`.
+- `cuda_package_version`: Optional. Default `latest` which will install the latest packages if not installed but won't upgrade already-installed packages. Use `'none'` to skip installing CUDA.
 - `cuda_persistenced_state`: Optional. State of systemd `nvidia-persistenced` service. Values as [ansible.builtin.systemd:state](https://docs.ansible.com/ansible/latest/collections/ansible/builtin/systemd_module.html#parameter-state). Default `started`.