[Sheflug] RE: [Gllug] SuSE and serial ports

["French, Alastair" <nospam [at] racalinst.co.uk>]

Thanks to all those that gave me some pointers about a locked serial port.

I tried all of them and they all pointed to no process owning the port. I
checked the permissions and these were as ttyS0 which had no problems.

In a flash of inspiration I had a look at /proc/interrupts. The D-Link220P
NIC in non plug and play mode had decided that it's default IRQ would be 3,
as this registered wtih the bios after the serial ports it took the IRQ from
ttyS1. A quick change to IRQ 5 (via the setup program and all is now OK)

Thanks again to all those that helped, if may make life quicker in the
future.

Alastair

> -----Original Message-----
> From:	Vincent AE Scott [SMTP:vince [at] codex.net]
> Sent:	Monday, February 26, 2001 11:38 AM
> To:	'gllug'
> Cc:	'sheflug'; 'lbc'
> Subject:	Re: [Gllug] SuSE and serial ports
> 
> On Mon, 26 Feb 2001, French, Alastair wrote:
> 
> > Hi all
> > 
> > I am having a problem with SuSE 6.3 and serial ports, using "cu -l
> ttyS1" I
> > get the response "port in use"
> 
> 
> from what i remeber, cu, uses UUCP style locking.  it looks for a file in
> something like /var/spool/uucp/locks and if it exists trusts that soemone
> else is already using the device.  and ignores it.
> 
> 
> 
> > trying this with ttyS0 I can talk to the modem.
> 
> are you saying that you plugged the modem into COM1 and it worked?
> 
> 
> 
> > The system did have a mouse on ttyS1, but I have taken this out,
> connected
> > the modem, stopped gpm, removed the /dev/mouse link, but it still won't
> > work.
> 
> there's a few system commands that will help you diagnose those, and may
> similar future types of problems you may encounter:
> 
> # fuser /dev/ttyS0
> # fuser /dev/ttyS1
> 
> the above will tell you the pid(s) of processes that are currently using
> the file.  from this you should be able to better back track what's
> locking the device and remedy it.
> 
> 
> # strace cu -l ttyS1
> 
> this will 'trace' all the system calls the command is executing.
> again, this will show in 'C' speak what it's failing on.  hopefully it'll
> say soemthing about a file ( /var/spool/locks/LCK..ttyS1 ), that you can
> then run fuser on to see whats locking it.
> 
> 
> alternatively i could be wrong about the UUCp style locks, and it might
> just be a user/group permissions setting on the device file.  some distros
> have a group 'modem' which is allowed access to serial ports.
> 
> what does ls -l /dev/ttyS[01] say?
> 
> 
> > I have also switched to single user mode and checked the init scripts to
> > make sure nothing is using the port. This also dosn't work so I tried a
> full
> > reboot to switch off anything using the port, still no luck.
> 
> things like mgetty, arent really started by init scripts, but it will also
> lock the device, for doing dialin logins/PPP.
> 
> 
> HTH,
> -vince
> 
> 
> PGP key:  http://codex.net/pgp/pgp.asc
> 
> 
> -- 
> Gllug mailing list  -  Gllug [at] linux.co.uk
> http://list.ftech.net/mailman/listinfo/gllug


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