This USB device (a Palm) has 2 serial interfaces. Only one of them is to be used for data connection to the desktop. Right now, it's not possible, other than through hackery on the device name, to distinguish which is which. $ udevinfo -a -p `udevinfo -q path -n /dev/pilot0` > /tmp/pilot0 $ udevinfo -a -p `udevinfo -q path -n /dev/pilot1` > /tmp/pilot1 $ diff -u /tmp/pilot0 /tmp/pilot1 --- /tmp/pilot0 2005-05-06 16:31:15.946538800 +0100 +++ /tmp/pilot1 2005-05-06 16:31:19.326989050 +0100 @@ -5,13 +5,13 @@ Only attributes within one device section may be used together in one rule, to match the device for which the node will be created. - looking at class device '/sys/class/tty/ttyUSB0': - SYSFS{dev}="188:0" + looking at class device '/sys/class/tty/ttyUSB1': + SYSFS{dev}="188:1" follow the class device's "device" - looking at the device chain at '/sys/devices/pci0000:00/0000:00:1d.2/usb4/4-1/4-1:1.0/ttyUSB0': + looking at the device chain at '/sys/devices/pci0000:00/0000:00:1d.2/usb4/4-1/4-1:1.0/ttyUSB1': BUS="usb-serial" - ID="ttyUSB0" + ID="ttyUSB1" SYSFS{detach_state}="0" looking at the device chain at '/sys/devices/pci0000:00/0000:00:1d.2/usb4/4-1/4-1:1.0': Only differences are the ID of the USB connection, the minor number of the device, and the different device name.
I don't think RHEL should take leadership in defining these sorts of interfaces. It's something Fedora should do. However, if you have a concrete proposal, and it you have a buy-in from gpilot or evolution folks, I'm all ears. I can help to push this to Greg Kroah and thus to Linus. Please educate me here; links to mailing list archives would be helpful.
I can't yet get buy-in from the Evo/gnome-pilot folks, as there's no code there to detect the Palms. The buy-in (David?) would probably first be from HAL, where interested applications can get the information about the index. After that, it's quite simple to have a property saying "This is the data port to use". The main problem is that HAL can't know about that, because the kernel doesn't export this property. Something like an INDEX property would be good enough.
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