2009-09-30 06:25:52

by Pavan Savoy

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Subject: hci_h4p and firmware download


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 ?


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