mgetty on null modem

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On  8 Nov, Gert Doering wrote this to me (Magnus Therning):

>> On  7 Nov, Gert Doering wrote this to me (Magnus Therning):
>> >> 11/07 15:03:54 yS1   do_makelock: lock='/var/lock/LCK..ttyS1'
>> >> 11/07 15:03:54 yS1   lock made
>> >> 11/07 15:03:55 yS1  tio_get_rs232_lines: TIOCMGET failed: Input/output error
>> > That's really unusual.  I'd suspect line noise (disturbances on the DCD
>> > line), or a bad null modem cable.
>> Unfortunately I don't have a place where I can try that...
> 
> No friends around, no "distribution kernel" to try (vs. the one you
> compiled yourself)?

No right now

> Can you send us the output of "gcc -v"?

Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/2.7.2.3/specs
gcc version 2.7.2.3

> If serial ports stop working "suddenly", especially after a recompile of
> the kernel, it's usually a very good sign that something in the kernel
> broke.  Somebody else reported a very similar log file to the list
> yesterday, where all his modems stopped working right after a kernel
> recompilation - and his log looked exactly like yours.

This is kind of strange. The modem worked fine on ttyS1, and when I run
the kernel that I used then (just did a recompile to put some thernet
stuff in) it still doesn't work, but the errors are a bit different:

11/08 15:28:27 yS1  mgetty: experimental test release 1.1.14-Apr02
11/08 15:28:27 yS1  check for lockfiles
11/08 15:28:27 yS1   checklock: stat failed, no file
11/08 15:28:27 yS1  locking the line
11/08 15:28:27 yS1   makelock(ttyS1) called
11/08 15:28:27 yS1   do_makelock: lock='/var/lock/LCK..ttyS1'
11/08 15:28:27 yS1   lock made
11/08 15:28:28 yS1   tio_get_rs232_lines: status: RTS DTR
11/08 15:28:28 yS1  WARNING: DSR is off - modem turned off or bad cable?
11/08 15:28:28 yS1   tss: set speed to 38400 (017)
11/08 15:28:28 yS1   tio_set_flow_control( HARD )
11/08 15:28:28 yS1   waiting for line to clear (VTIME), read:
11/08 15:28:28 yS1   waiting for line to clear (VTIME), read:
11/08 15:28:28 yS1   removing lock file
11/08 15:28:28 yS1  waiting...
11/08 15:31:39 ##### failed dev=ttyS1, pid=227, got signal 15, exiting

> Try to start mgetty on the port that your mouse is currently connected to
> - if that doesn't give errors, it might be the serial port.   But I still
> suspect the kernel.

The mouse IS a serial mouse, but mgetty won't start on that port anyway.
It prints the same things as ttyS1, but the mouse works fine both when
I start gpm and within X (of course I killed all mouse related programs
before trying).

It is quite an old computer 486/66, and all cards are the same age
(around 1994).

-- 
Magnus Therning ( etrius@hem2.passagen.se )
http://hem2.passagen.se/etrius/