A few people have noted that the com driver in -current seems to lose
badly with PPP.  This was due to a bug (which I have just fixed) that
would cause it to retransmit some bytes when the other side deasserted
CTS.  This would typically happen with a modem, where the DTE speed is
higher than the actual transmission speed, and flow control has to be
used.  It would typically not happen with two machines
cross-connected.

If you've been experiencing a problem which might be attributable to
this, please try the latest version of the driver (revision 1.100),
and let me know whether or not it helps.  I've included the (rather
simple) patch below.


Index: com.c
===================================================================
RCS file: /cvsroot/src/sys/dev/isa/com.c,v
retrieving revision 1.99
retrieving revision 1.100
diff -c -2 -r1.99 -r1.100
*** com.c	1997/04/04 20:56:34	1.99
--- com.c	1997/05/26 14:54:46	1.100
***************
*** 1,3 ****
! /*	$NetBSD: com.c,v 1.99 1997/04/04 20:56:34 mycroft Exp $	*/
  
  /*-
--- 1,3 ----
! /*	$NetBSD: com.c,v 1.100 1997/05/26 14:54:46 mycroft Exp $	*/
  
  /*-
***************
*** 1248,1252 ****
  		} else {
  			sc->sc_tx_stopped = 1;
- 			comstop(tp, 0);
  		}
  	}
--- 1248,1251 ----