🚀 go-pugleaf

In comp.unix.admin ssigv!lewis (Don Lewis) writes:

>In article <1991Nov6.181150.25181@moon.nbn.com> jh@moon.nbn.com (John Harkin) writes:
>>rk@lexicon.com (Bob Kukura) writes:
>>
>>>We have a Telebit T2500 connected via a built-in serial port at 19200
>>>baud with hardware flow control to a SPARCstation 2 running SunOS
>>>4.1.1b.
>>
>>>Every day or two, it gets into a state where it won't answer the phone
>>>on incoming calls although outgoing calls work fine.  Usually the
>>>modem's DTR light is on, but in this state, it is off except during
>>>outgoing calls.

>I've had this same problem, with the same hardware.

>>>Sometimes, killing the getty on the port fixes the problem, but
>>>usually the DTR light stays out and init refuses to start a new getty.

>Killing the getty never worked for me.

>>This fix causes the kernel to wait longer to turn on DTR.  This gives
>>the T2500 more time to reset, it sometimes takes a while to recover
>>from a PEP connection.

>This is not the same problem that I had.  The problem wasn't that
>DTR was turned on too quickly, it never comes back on at all except
>on outgoing calls.  Killing getty and resetting the modem had no
>effect.  The only way to get inbound connections to work was to
>reboot the cpu.

Thanks for posting about the Sun patch, I hadn't seen that.  It appears
to have been released after I fixed my problems.

DTR turning on too quickly is what causes it not to come back on at all.
Every once in a while, the garbage from the modem would cause the getty
to hang in the kernel.  It would still dial out OK, but would never 
assert DTR so no dialins could occur.  Rebooting (loading a new kernel)
is the only way to clear the kernel hang.

Since I extended the DTR down time to 6, I have had NO hangs.

Here's the patch info for those who tuned in late:

>    Patch-ID# 100358-01
>    Keywords: dialin dialout drops DTR
>    Synopsis: SUnOS 4.1.1: unable to dialin DTR dropped
>    Date:26/July/91

>    SunOS release: 4.1.1

>    Topic: DTR dropped and unable to close on dialin/dialout lines

>    BugID's fixed with this patch: 1060689

>    Architectures for which this patch is available: sun4 sun4c sun3 sun3x
-- 
John Harkin   +1 415 472-2452   moon!jh   uunet!nbn!jh   jh@nbn.com
North Bay Network - News and mail for Marin county and vicinity