we create the pty on the fly when it is first opened.
If you run out of ptys now, just MAKEDEV some more.
This also demonstrate the use of dev_t->si_tty_tty and dev_t->si_drv1
in a device driver.
{ port_name = "IO_TIMER", port_number = 1 } and only worked because
it was reassembled to "IO_TIMER1". Trailing digits always work, but
this is too magic to depend on.
Don't quote port names that don't have a digit in them.
The last consumer of this code (the old SCSI system) has left us and
the CAM code does it's own bouncing. The isa dma system has been
doing it's own bouncing for a while too.
Reviewed by: core
