I see that the nokia's hci_h4p which makes use of the UART transport for BT chip and doesn't make use of the line-discipline, downloads the firmware to chip by making use of the firmware class in kernel.
Why do we require this ? Most manufacturers have their drivers compliant to hci-line discipline and similar to h4 protocol driver and the firmware download is often done from hciattach in user-space.
a. what is the advantage of not having hciattach in system ?
[This kind of makes the UART connected to BT chip un-useable as a normal TTY device, and BT down would only mean hciconfig hci0 down, leaving the HCI-Core tasklets running and consuming more power, unlike killing of hciattach and hci-daemon]
b. what is the advantage of having firmware download in kernel ?
Connect more, do more and share more with Yahoo! India Mail. Learn more. http://in.overview.mail.yahoo.com/