>One thing I have noticed, however, in common with what Branden was >mentioning was that the macserial driver sees 2 serial devices on this >FireWire iBook - ttyS0 (aka tts/0), which is the modem (I'm using it now, >so it does work), and ttyS1, which doesn't seem to be anything. This >laptop has 6 ports - USB, FireWire, audio/composite video, Ethernet, >modem, and power. Is there logic somewhere in its mainboard for a serial >port that just doesn't have a connector? Does the macserial module just >blindly assume there will always be 2 serial ports? Or is there something >else up here?
The SCC chip in the KeyLargo ASIC provides 2 serial ports. The second one use usually connected to the irda transceiver on laptops, but it looks like Apple decided to save that cost on iBooks. The port does exist, it is referenced in the device-tree, it's just that nothing is connected to it. Ben.
