What makes a serial device enter the closing state?

What makes a serial device enter the closing state?

Post by Clark B. Wier » Sat, 01 Oct 1994 03:40:50

Under Novell's Unixware 1.1, I am having a problem with a serial device entering
the closing state when I don't want it to.

I am trying to communicate over a long link to a remote terminal.  The link will
be RS-485.  I am converting RS-232 to RS485, then converting back at the remote
location.  I have this mocked up on my desk right now (with a much shorter link
between the converters).

When I just use a null modem, the system works just fine.  When I put the RS-485
portion in place of the null modem, the port stops working after the first 12
characters (I think this is more time related than number of characters related
because, if I add a delay after the first few characters, the port will have
already stopped working).

To make matters for interesting, I can use C-Kermit to talk to the port through
the RS-485 link all day without any problem.  Obviously, they are doing
something that I'm not; I just can't determine what that is.

Any help, ideas, etc. will be greatly appreciated.

Clark B. Wierda       Computer Specialist       These opinions are mine and do
401 Hardin Road       Phone:     501-228-3642   not necessarily represent those
Little Rock, AR 72211 EDOC:      CBWIERDA            of the Federal government


1. apm: busy: Unable to enter requested state

Firmware == bios?

None that I know of ... But the system does kind of suspend
(hdd is spun down, monitor shuts down, ....) but when the system
resumes (press key, move mouse) the temperature of the cpu is
still the same it was before the suspend. Sometime ago the
cpu cooled down to roomtemperature (sys temp also). But this
does not happen any more :-(

When I press the suspend button the message appears
almost instantly (message appears several times). But
I checked 2.4.18-pre7 and there the message does not
appear but the cpu does not cool down either. The kernel
that generates this message was 2.4.17-rmap12a.

That is exactly what I would like it to do and which it
partly does. But the cpu does not cool down (it seems as
if it is not shut down - do I have to use a config option
for this?).

# CONFIG_ACPI is not set

Do I have to enable one of these?




Well, yeah ... I suppose there's no point in getting greedy, is there?

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