Hi Miao-chen, > This moves msft_do_close() from hci_dev_do_close() to > hci_unregister_dev() to avoid clearing MSFT extension info. This also > avoids retrieving MSFT info upon every msft_do_open() if MSFT extension > has been initialized. what is the actual benefit of this? It is fundamentally one extra HCI command and that one does no harm. You are trying to outsmart the hdev->setup vs the !hdev->setup case. I don’t think this is a good idea. So unless I see a real argument why we want to do this, I am leaving this patch out. And on a side note, I named these function exactly this way so they are symmetric with hci_dev_do_{open,close}. Regards Marcel