Terminal Driver for MCP/ALM-II?

[Leonard Sitongia]

System:                 Sun-4/280S
OS:                     4.0.1+patches

We have a terminal port selector connected to our ALMs.  The port selector
wants to see DTR (Data Terminal Ready) drop for a moment when logout
occurs, then when DTR is restored it will make the port available again.

I have seen ocassions in which a user logs out, DTR drops and it never
comes back.  Also, I have an idle-terminal killer will drops DTR, sleeps,
and tries to raise DTR, which usually works, but sometimes cannot raise
DTR.  Is it the ALMs responsibility to restore DTR, or does the port
selector have to do something to the ALM before the ALM will restore DTR?

Of course, most times DTR does get restored.

More information, for lines which have DTR off:
1) these lines do not have soft carrier enabled in the kernel configuration.
2) syslog reports I/O error from getty periodically (every 10 minutes?).
3) I cannot open the line to do an ioctl to raise DTR (I/O error).

We've installed 4.0.1 and the patch tape "YAPT 5th edition".  In the bug
list 1008825 says that DTR on modem lines is asserted while port is not
open.

How do I get DTR back up, short of rebooting?  Im in a catch-22 because I
cant open the line with DTR down and cant raise DTR without openning the
line.  Is there an alternative (of course I've tried killing getty on the
line and doing the old off/on-in-/etc/ttytab-"kill -1 1")?

Thank you for your time,
-Leonard E. Sitongia    System Programmer		 (303) 497-1509
USPS Mail: High Altitude Observatory P.O. Box 3000 Boulder CO  80307
Internet:               sitongia at hao.ucar.edu
SPAN:			NSFGW::"hao.ucar.edu!sitongia"	[NSFGW=9580]