> Date: Thu, 23 Oct 1997 13:42:45 -0400
> From: Steven Grunza <steveng@formail.formation.com>

> Same here, except they were zs0b:  fifo overrun.  I had a 14.4 modem on
> ttyb with RTS/CTS flow control.  The SPARC is a SPARCstation 1.

Oh...  I was confused.  When there is a problem with H/W flow control,
(i.e. crtscts not turned on, or wrong cable wiring) then the message
one will see is "ring overrun", not "fifo overrun" as I had thought.
(Maybe "fifo overrun" should be "chip overrun" instead.)

The cause of "fifo overrun" message is excessive latency in servicing
interrupts from the ZS chip.  The cause of that could be anywhere,
i.e. interrupts disabled too long somewhere, or who knows what.
What else was going on in the system at the time?

Lower baud rates will probably eliminate the "fifo overrun" problem.
Have you tried that?  What is the highest rate that makes the fifo
overrun errors become infrequent?

Gordon