SCO UNIX interrupt priority level problem

[Mark A. Johnson]

Hello,
	I have a question that involves a character device and what the highest
interrupt priority level(ipl) should be.  Our device is running under SCO UNIX
3.2.0 and a 20MHZ 386 with no cache.  What our problem is we keep getting
receiver overruns at 19200 baud.  At 9600 baud we are fine.  We currently
have our ipl set at 7.  When we raise our ipl to 8 it runs fine at 19.2K.
I have spent numerous hours searching though the SCO documentation to find out
whether we should keep our ipl that high(Highest ipl in /etc/conf/cf.d/sdevice
is 7).  (I am afraid that this may be rude and evil to have it this high :-)
My question is whether we should raise it that high or not.  Could we
be possibly be hosing some other device?  (ie not letting the clock interrupt)
We are also not sure what the NMI is set at in SCO.  Could this be a potential
problem?  Do you think it could be a remote possibility that SCO UNIX 3.2.2
upgrade could solve our problem?

	I would appreciate email as opposed to posting as I do not think that this
would be much interest in discussion to the rest of the newsgroup. 
	Thanks in advance.

                             Mark Johnson 
                   Intercomputer Communications Corp.
                        Cincinnati, Ohio  45236
     (513)-745-0500           maj at ICC.COM          ...!ukma!spca6!icc!maj