pytorch_lightning Trainer doesn't recognize hpu

[jingkang99]

gaudi2 system with fresh pytorch installation
pip list | grep -P "torch|torchvision|torchmetrics|protobuf"

Basic Pytorch training is fine - followed steps on https://docs.habana.ai/en/latest/PyTorch/Getting_Started_with_PyTorch_and_Gaudi/Getting_Started_with_PyTorch.html

from pytorch_lightning import LightningModule, Trainer

Try following pytorch-lightening hello world example, get some error
https://github.com/HabanaAI/Gaudi-tutorials/blob/main/Lightning/Introduction/mnist-hello-world.ipynb

but "hpu" not recognized

what should be installed?