[ale] locked serial port

[Alan Bowman]

> I have a locked serial port that I cannot seem to unlock.  I've looked
> in all the customary spots for locks: i.e. /var/lock and
> /var/spool/uucp.  The Serial HOWTO talked about lock files in
> /usr/spool/uucp but I don't have one of those.  I have tried deleting
> the device and re-creating it.  I have shutdown and restarted.  I can't
> seem to get anywhere.
 
 Are the two machines still connected?  If so, the -other- machine may
be where the locked port is.  Try this, on your end: go superuser, and
at the #..

# fuser -k /dev/cua1 <return> (the next line is the stout for fuser)
/dev/cua1: some numbers here,representing PID's,and your prompt below
# (you get your pound sign back)

At the next #, run the fuser command again.  If the PID numbers stay the
same, then the port is still locked. At this point the only thing that
unlocks it is a power off shutdown. If it's still locked after that,
then the next likely culprits are either a bad port(s)/cable(s).  If,
however, the fuser command gives you a different set of PID's every
time, then the port 'thinks' it is open.  fuser kills the process
running on that port, and starts a new one.  In this case, it should
start a new getty, since you're going for a login on a serial port.  If
fuser doesn't give you login on the other machine, check cables and
connections.  Also check the inittab.  I can't say for sure how the
inittab is set up on RH, but it should have entries for all the consoles
and the serial ports.  
  What kind of cable are you using?  I know that at work we have to
change the crossover for the pins if the cable is going from the comm
port on one PC to the comm port on another. This, though, is using RJ45
modular adapters and Cat5 cable, not a standard serial cable. 
Unfortunatly, I can't remember off the top of my head just what pins
they are.   
  

 > Can you suggest a way to unlock my /dev/cua1 port?
  Well, there's one suggestion.  I'm sure someone more familiar with RH
will have a better one.  I'm a Slackware kind of guy, but guess that the
two distro's should behave fairly similarly. 

...alan
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