USB serial device naming

[Hans Petter Selasky]

On Monday 14 December 2009 08:42:04 Ed Schouten wrote:
> Hello Trevor,
>
> * Trevor Blackwell <tlb at tlb.org> wrote:
> > I can't seem to find a way to match USB serial ports & tty names. I
> > have two serial USB devices, which I can distinguish easily from
> > "usbconfig show_ifdrv"
> >
> > 	<snip>
> >
> > and they result in two ttys:
> > 	/dev/cuaU0
> > 	/dev/cuaU1
>
> Be sure to keep in mind: the `real' TTY devices are ttyU0 and ttyU1. The
> cua* devices are callout devices, which unlike the tty* devices don't
> wait for a carrier detect signal during open().
>
> My opinion is that the USB serial driver shouldn't use a bitmask to keep
> track of which unit number are available, because we've got a nice KPI
> for that:
>
> 	http://www.freebsd.org/cgi/man.cgi?query=new_unrhdr
>
> Unfortunately I cannot answer your question. Hopefully Hans can. ;-)

That's OK, but the real problem is that TTY is not a visible child of UPLCOM 
for example. I would suggest adding a new IOCTL or maybe you have a better 
idea, where we can pass the "device_get_nameunit()" string, and then TTY can 
store it and pass it to userland.

Also TTY should have a printout in dmesg, which unit is create if this string 
is specified.

--HPS